pkinative-mcp

MCP server for PKI — inspect and verify X.509 certificates, CSRs, CRLs, OCSP responses, CMS SignedData and RFC 3161 time-stamps; build and validate certificate chains (RFC 5280 path validation, name and purpose checks, offline CRL and OCSP revocation); create certificates, CSRs, CMS signatures, OCSP and time-stamp requests; open PKCS#8 and PKCS#12 without ever returning a key byte; decode ASN.1, PEM and OIDs — 34 tools and 7 prompts on the pkinative engine (zero-dependency, pure TypeScript, Web Crypto for every signature; OpenSSL 3 interoperability validated in CI), for Claude Desktop, Cursor, ChatGPT and any Model Context Protocol client. No network, ever.

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✨ Features

pkinative-mcp exposes 34 tools to any MCP host, in six groups. The kind says how the result is shaped: a read tool returns facts (structuredContent, projectable with verbosity / fields); a verdict tool returns valid + reasons[] and is never isError for a negative verdict; an artefact tool delivers DER or PEM once, inline or into the sandbox. The last column names the refusal codes an agent branches on (the full table is in docs/AGENT_CONTRACT.md).

Encodings

Tool	Kind	What it does	Key refusal codes
convert_pem	read	mode: 'decode' lists every block of a PEM text (label, DER size, offset, SHA-256) and extractIndex delivers one as DER / PEM / hex; mode: 'encode' wraps exactly one DER value into one strict RFC 7468 block under label. A private-key block is listed, never extracted and never produced; key material anywhere in the input is refused.	SECURITY_VIOLATION, NOT_FOUND, VALIDATION_ERROR, PKI_PEM_UNEXPECTED_LABEL, PKI_PEM_*
resolve_oid	read	Object identifiers in one call: name (registered names, ≤ 1000 per call), validate (X.660 grammar, reported never thrown), list (the engine registry, paged 200 / 2000), encode (dotted → hex, content or whole TLV, RELATIVE-OID), decode (hex → dotted + name).	VALIDATION_ERROR, PKI_OID_INVALID, PKI_ASN1_*
compute_fingerprint	read	fingerprint of the exact DER (SHA-256 default; SHA-1 / 384 / 512), key-id (the RFC 5280 §4.2.1.2 identifier of the public key of a certificate, CSR or PUBLIC KEY), shake256 (outputLength bytes, the Ed448 CMS digest). Any object may be digested; no input byte is returned.	VALIDATION_ERROR, PKI_X509_*, PKI_ASN1_*
decode_asn1	read	The X.690 node tree of any DER (BER with encodingRules: 'ber'): offsets, tags, previews, OID names, ≤ 20 000 nodes; nodePath narrows to a subtree, read applies a typed reader, reencode: true re-encodes the node as an artefact. Refuses a private key or a PKCS#12 (by label, or when the DER parses as one).	SECURITY_VIOLATION, NOT_FOUND, PKI_ASN1_UNEXPECTED_TAG, PKI_API_MISUSE, PKI_ASN1_*
encode_asn1	artefact	A JSON node spec (boolean, integer, bit-string, octet-string, oid, string, time, sequence / set / set-of, explicit / implicit, tlv, der) encoded to DER through the engine's own encoders — deterministic; the inverse of decode_asn1.	VALIDATION_ERROR (naming the JSON path), SECURITY_VIOLATION, PKI_LIMIT_EXCEEDED, PKI_ASN1_*, PKI_OID_INVALID

Certificates and requests

Tool	Kind	What it does	Key refusal codes
inspect_certificate	read	The RFC 5280 report of one certificate: serial, algorithms, issuer / subject (RFC 4514 + RDNs), validity, public key, the 19 extension kinds decoded (rawExtensions: true keeps them raw), fingerprints, diagnostics; extension returns one; issuer / checkSelfSignature adds one signature check — which is not trust.	NOT_FOUND, PKI_PEM_UNEXPECTED_LABEL, PKI_X509_*, PKI_CRYPTO_ALGORITHM_REFUSED
create_certificate	artefact	Issue an X.509 v3 certificate from spec (subject, validity, extensions), signed by signer (a PKCS#8 key or a PKCS#12 file imported as a non-extractable Web Crypto key): self-signed CA, or a leaf issued from a certificate / CSR / PUBLIC KEY. Serial 'random' by default; verified against the issuer before the bytes return.	KEY_MISMATCH, RSA_SCHEME_REQUIRED, KEY_TYPE_REQUIRED, SECRET_REQUIRED, UNSUPPORTED_KEY, VALIDATION_ERROR
encode_x509_structure	artefact	One X.509 building block (name, validity, spki, algorithm-identifier, extension(s), basic-constraints, key-usage, extended-key-usage, subject-alt-name, SKI / AKI, signature-algorithm) encoded deterministically from a closed spec; hex by default. Nothing here signs.	VALIDATION_ERROR (naming the member), KEY_TYPE_REQUIRED, SECRET_REQUIRED, RSA_SCHEME_REQUIRED
decode_extension	read	One extnValue content (hex or DER) decoded by its OID exactly as inspect_certificate would; critical is checked against the kind's RFC 5280 rule (a diagnostic, not a refusal).	PKI_X509_EXTENSION_MALFORMED, VALIDATION_ERROR
check_certificate_name	verdict	The RFC 6125 identity verdict: certificate + host / ip (SAN dNSName / iPAddress, wildcards, an opt-in CN fallback held to the chain's name constraints), or the match form presented + reference with no certificate.	PKI_REASON_NAME_MISMATCH (in reasons[]), VALIDATION_ERROR
check_certificate_purpose	verdict	May certificate be used for purpose (serverAuth, clientAuth, codeSigning, emailProtection, timeStamping, ocspSigning, any, or an OID) along [certificate, ...chain]? restrictIssuers (default true) applies a CA's own EKU to what it issued.	PKI_REASON_PURPOSE_NOT_PERMITTED (in reasons[]), VALIDATION_ERROR
inspect_csr	read	The RFC 2986 report of one PKCS#10 request: subject, key, attributes, the extensions requested, whether a challengePassword is present (never its text), and by default the proof of possession (signature.valid).	PKI_REASON_SIGNATURE_NOT_CHECKED (in reasons[]), PKI_X509_*, PKI_PEM_UNEXPECTED_LABEL
create_csr	artefact	A PKCS#10 request from spec (subject, the extensions to request) signed by signer; the public key is derived from a plain key, taken from the PKCS#12 certificate or given as subjectPublicKey; the proof of possession is verified before the bytes return.	KEY_MISMATCH, RSA_SCHEME_REQUIRED, SECRET_REQUIRED, KEY_TYPE_REQUIRED, VALIDATION_ERROR

Paths, CRLs and OCSP

Tool	Kind	What it does	Key refusal codes
verify_certificate_chain	verdict	The one-call trust verdict: a path from leaf through candidates to one of your trustAnchors, every signature verified, RFC 5280 §6 validation at at (validity, constraints, key usage, names, policies), serverName (RFC 6125) and purposes, and revocation from the CRL / OCSP bytes you supply (requireRevocation demands evidence for the end-entity certificate).	PKI_REASON_* in reasons[] (NO_TRUST_ANCHOR, EXPIRED, NOT_YET_VALID, REVOKED, REVOCATION_UNKNOWN, NAME_MISMATCH, …), VALIDATION_ERROR
build_certificate_path	verdict	Path discovery only: which intermediates lead from leaf to an anchor under the structural rules at at. No signature is checked — valid is always false, the verdict is found and structuralReasons.	PKI_REASON_SIGNATURE_NOT_CHECKED (always), PKI_REASON_NO_TRUST_ANCHOR
validate_certificate_path	verdict	RFC 5280 §6.1 validation of a path you ordered (leaf first) against your anchors at at; every link signature verified first (checkSignatures: false gives the structural verdict with failingReasons). No revocation here.	PKI_REASON_SIGNATURE_INVALID, PKI_REASON_SIGNATURE_NOT_CHECKED, VALIDATION_ERROR
inspect_crl	read	The RFC 5280 §5 report of one CRL: issuer, updates, CRL number, delta indicator, IDP, entry count (walked, never all decoded), extensions; find looks one serial up; issuer adds one signature check.	VALIDATION_ERROR, PKI_X509_*, PKI_CRYPTO_ALGORITHM_REFUSED
check_crl_revocation	verdict	One certificate against one base crl (and an optional delta) you fetched, at at: scope, freshness (staleTolerance), the signature verified against issuer, the serial looked up. A delta whose signature does not verify against issuer is not applied: valid: false with PKI_REASON_REVOCATION_UNKNOWN on delta.	PKI_REASON_REVOKED, PKI_REASON_REVOCATION_UNKNOWN (in reasons[]), VALIDATION_ERROR (a delta without deltaCRLIndicator)
create_ocsp_request	artefact	The DER OCSPRequest (RFC 6960) for certificate under issuer: CertID with SHA-1 (default) or SHA-256, an RFC 8954 nonce ('random' or hex), certIdOnly. You POST the bytes to the responder; summary.nonceHex / certIdHex match the answer.	VALIDATION_ERROR
inspect_ocsp_response	read	The RFC 6960 report of one response: status, responder id, producedAt, every SingleResponse (CertID, status, updates), extensions, embedded certificates, nonce presence; responder adds one signature check.	PKI_* (PKI_ASN1_*, PKI_X509_*), VALIDATION_ERROR
check_ocsp_status	verdict	One response for one certificate: the CertID recomputed from issuer, the signature verified (responder, the embedded certificates or the issuer), the signer authorised (RFC 6960 §4.2.2.2), status, freshness at at, nonce (nonce, requireNonce).	PKI_REASON_REVOKED and the other PKI_REASON_* in reasons[], VALIDATION_ERROR

CMS and time-stamps

Tool	Kind	What it does	Key refusal codes
sign_cms	artefact	An RFC 5652 SignedData over content (attached or detached) or a precomputed contentDigest, one signer (PKCS#8 key or PKCS#12), certificate, chain and crls parsed then embedded; signed attributes always written (contentType, messageDigest, signingTime, SigningCertificateV2, CMSAlgorithmProtection); verified against the signer certificate before the bytes return.	KEY_MISMATCH, RSA_SCHEME_REQUIRED, SECRET_REQUIRED, VALIDATION_ERROR, PKI_API_MISUSE, ENGINE_ERROR
verify_cms	verdict	The one-call verdict on a SignedData: for every signer the signed attributes, the content digest (attached, or content / contentDigest), the signature, the chain to your trustAnchors at at, every counter time-stamp, and revocation from the bytes you supply plus those the message carries; atTimeStamp: true is long-term validation.	PKI_REASON_* in reasons[] (per signer too; intact tells unaltered from untrusted), PKI_ASN1_TRAILING_DATA, VALIDATION_ERROR
inspect_cms	read	The RFC 5652 report: content type and length, digest algorithms, embedded certificates, CRL / OCSP counts, every signer (identifier, algorithms, signing time as claimed, attributes, time-stamp count, the signature value a counter time-stamp stamps); signerCertificate adds one key check on the signer signerIndex names.	NOT_FOUND (a signerIndex past the last signer, with signerCertificate), PKI_ASN1_TRAILING_DATA, PKI_*
amend_cms	artefact	The one edit a signed message legitimately receives afterwards: add-unsigned-attribute (a DER Attribute as hex) or add-timestamp (a TimeStampToken or the whole TimeStampResp) on signer signerIndex, every signed octet unchanged; the token's imprint is checked against the signature value before anything is written.	VALIDATION_ERROR (data.detail PKI_REASON_TSP_IMPRINT_MISMATCH), NOT_FOUND, PKI_API_MISUSE
create_timestamp_request	artefact	The RFC 3161 TimeStampReq you POST to a TSA yourself: imprint over data or digestHex (SHA-256 / 384 / 512), nonce ('random', decimal or hex), policy, certReq.	VALIDATION_ERROR (a digest of the wrong length)
inspect_timestamp	read	A TimeStampResp, a TimeStampToken or a bare TSTInfo (auto-detected, or as): status, policy, imprint, serial, genTime, accuracy, nonce, the TSA name as stated, the CMS envelope. Parsing proves nothing.	PKI_*, PKI_STRICT_DIAGNOSTIC (with strict: true)
verify_timestamp	verdict	token or response judged against what you say was stamped (request, data or digestHex — at least one), the TSA signature, its chain to your anchors at at with a critical timeStamping EKU, and revocation from the bytes you supply.	PKI_REASON_TSP_IMPRINT_MISMATCH, PKI_REASON_TSP_NOT_GRANTED and the other PKI_REASON_* in reasons[], VALIDATION_ERROR

Private keys and PKCS#12

Tool	Kind	What it does	Key refusal codes
inspect_private_key	read	Describe a PKCS#8 key without its password (with PKINATIVE_MCP_PASSWORD unset — the variable counts as the password of every password-accepting tool): format, kind, curve, algorithm, the PBES2 parameters of an encrypted key (or the legacy scheme pkinative refuses); tryImport: true imports it as a non-extractable Web Crypto key and reports the handle. No result ever carries a key byte.	SECRET_REQUIRED, KEY_TYPE_REQUIRED, RSA_SCHEME_REQUIRED, PKI_CRYPTO_DECRYPTION_FAILED, PKI_KEY_ENCRYPTION_UNSUPPORTED
inspect_pkcs12	read	Describe a .p12 / .pfx without its password (the operator's PKINATIVE_MCP_PASSWORD counts as one, so it must be unset): MAC construction (PBMAC1, or the legacy RFC 7292 MAC), every SafeContents and its scheme, the bags of the plain ones; with a password, macVerified and opened (allow-list views of every bag) — a wrong password on an encrypted SafeContents is PKI_CRYPTO_DECRYPTION_FAILED.	PKI_CRYPTO_DECRYPTION_FAILED, PKI_KEY_MAC_UNSUPPORTED, PKI_KEY_ENCRYPTION_UNSUPPORTED
open_pkcs12	verdict	Open a PKCS#12 in one call: MAC verified, PBES2 SafeContents decrypted, every key unwrapped straight into a non-extractable Web Crypto key (described, never exported), certificates parsed, CRLs counted; exportCertificates: true attaches a PEM bundle of the certificates and CRLs — never a key.	SECRET_REQUIRED; in reasons[]: PKI_REASON_PKCS12_MAC_MISMATCH, PKI_REASON_PKCS12_ENCRYPTION_UNSUPPORTED, PKI_REASON_PKCS12_INTEGRITY_UNVERIFIED, PKI_REASON_PKCS12_RSA_SCHEME_UNSPECIFIED

Meta

Tool	Kind	What it does	Key refusal codes
describe_engine	engine	Offline preflight: versions, the host's Web Crypto capabilities, the engine's 22 default limits, the operator ceilings, every server cap, sandbox / cache / pinned-instant state, the 57 PKI_* / 43 PKI_REASON_* / 97 PKI_DIAG_* vocabularies, the 21 wrapper codes, the doctrine refusals and the deliberately unexposed engine surface. network is always 'none'. Never cached.	VALIDATION_ERROR
explain_code	explain	Any code this server can emit, explained from the registries vendored at the pkinative v1.0.0 tag (class, standard, CWE, remedy, the MCP input that lifts it); list: true enumerates one vocabulary.	NOT_FOUND
draft_governance_issue	governance	A local GitHub issue draft plus a compliance report for pkinative, pkinative-cli or pkinative-mcp — never submitted; a human files it under their own identity.	GOVERNANCE_VIOLATION, MISSING_OUTPUT_PATH, INVALID_EXTENSION, OUTPUT_EXISTS, SECURITY_VIOLATION

What every tool guarantees:

• 🌐 No network, ever — no CRL / OCSP / AIA / TSA fetch, no telemetry, no GitHub, no URL from any argument, no operator-configurable endpoint. Revocation evidence and time-stamp tokens are inputs; create_ocsp_request and create_timestamp_request produce bytes you transport. Every tool advertises openWorldHint: false.
• 🔑 No key byte leaves — signing keys are non-extractable Web Crypto handles; every key / PKCS#12 report is an allow-list view; key-bearing files (.key .p8 .p12 .pfx) are never written and never served as resources; convert_pem, decode_asn1 and encode_asn1 refuse private-key material. There is no key generation and no key export.
• 🧭 Verdicts are reports, errors are refusals — a negative verdict is valid: false + reasons[] with the engine's PKI_REASON_* codes (43 of them); isError is reserved for an input the engine refuses (one of the 57 PKI_* codes, passed through verbatim with data.errorClass and a remedy) or a wrapper refusal (21 codes, each with a remedy). Branch on the code, never on the message.
• 📐 Doctrine, surfaced not hidden — SHA-1 only with allowSha1: true; RSA needs an explicit rsaScheme ('pkcs1' | 'pss', no default); PBES2 and PBMAC1 only (a legacy RC2 / 3DES PKCS#12 is refused with the OpenSSL 3.4 conversion remedy); DSA and ML-DSA are parsed, never verified; diagnostics (97 PKI_DIAG_* codes) are not errors unless strict: true; the engine's 22 limits raise per call and never above the operator ceilings.
• 🪙 Token-frugal — read and verdict tools accept verbosity: 'summary' and fields: [...]; artefacts arrive once as an embedded resource block or a resource_link, never duplicated into structuredContent.
• 🔁 Reproducible on request — pin at, notBefore, signingTime, serialNumber and nonce (or let the operator pin the instant with PKINATIVE_MCP_AT) and an artefact or a verdict is a pure function of its inputs; structuredContent.sha256 is the proof (docs/guides/REPRODUCIBLE.md).
• 🧪 OpenSSL 3 is the judge — every artefact the server writes is read back by OpenSSL 3.x in CI (23 conformant artefacts, 5 refused canaries, 12 command families), blocking on Linux and Windows.

All artefact-producing tools support two output modes and three encodings:

• base64 (default) — the artefact is returned once as an embedded resource content block (PEM as text, DER as blob, with its MIME type: application/pkix-cert, application/pkcs10, application/pkcs7-signature, application/pkix-crl, application/ocsp-request, application/timestamp-query, …); structuredContent carries { mode, encoding, sizeBytes, sha256, summary, diagnostics } — with encoding: 'hex' the bytes land in structuredContent.hex instead (inline only, ≤ 64 KiB).
• file — the artefact is written inside the sandbox configured by PKINATIVE_MCP_OUTPUT_DIR (exclusive create, never overwritten → OUTPUT_EXISTS; ≤ 1 GiB) and the result carries a resource_link. File I/O is disabled unless this variable is set; absolute paths, traversal, NUL bytes, a key-bearing or unknown extension and a symlink or junction whose real path leaves the sandbox are all rejected. The same sandbox serves every path input, so a create_csr → create_certificate → verify_certificate_chain chain never re-sends the bytes.

Token-frugal reads. The read and verdict tools (and describe_engine, explain_code) accept two optional inputs:

• verbosity: 'summary' — a compact scalar-only verdict. E.g. verify_certificate_chain → { valid, reasonCodes, pathLength, evaluatedAt, revocationEvidence, diagnosticCount }; inspect_certificate → subject, issuer, serial, validity, key, extension kinds.
• fields: ['a', 'b.c'] — projects the structured result to named dot-paths (≤ 16; arrays map over elements); composes after verbosity. Every path that matched nothing — nested paths included — is omitted and reported in _meta.unmatchedFields (with _meta.availableFields); a path holding a __proto__, constructor or prototype segment is VALIDATION_ERROR.

Smallest "can I trust this server certificate?" probe: { "leaf": {…}, "trustAnchors": [{…}], "at": "2027-01-01T00:00:00Z", "serverName": { "host": "example.test" }, "verbosity": "summary", "fields": ["valid", "reasonCodes"] } on verify_certificate_chain.

The server also ships seven MCP prompts — governance_contract, draft_issue_workflow, verify_before_trust, issue_certificate, sign_and_timestamp, offline_revocation, open_keys_safely — and exposes every non-secret file in the sandbox as a pkinative://output/{+path} resource.

Why pkinative?

pkinative-mcp inherits every guarantee of the underlying engine:

• Zero runtime dependencies in the engine — pure TypeScript, no native bindings; Web Crypto for every signature, so no secret-dependent arithmetic runs in JavaScript (this server adds only the MCP SDK and zod: three runtime dependencies in total).
• RFC 5280 path validation (building, §6.1 validation, name constraints, policies), RFC 6125 names, RFC 6960 OCSP, RFC 5652 CMS, RFC 3161 time-stamps, RFC 2986 CSRs, RFC 5958 / 8018 PKCS#8 with PBES2, RFC 7292 / 9579 PKCS#12 with PBMAC1, strict X.690 DER with opt-in BER.
• 22 named, CWE-tagged limits on every parser loop — raised only by explicit input, never silently.
• A frozen vocabulary — 57 PKI_* error codes, 43 PKI_REASON_* verdict reasons and 97 PKI_DIAG_* diagnostics, vendored at the v1.0.0 tag and passed through verbatim.
• What it will NOT do: no key generation, no key export, no writer for PKCS#8 / PKCS#12 / CRL / OCSP response / time-stamp response, no DSA / ML-DSA verification, no network access, ever.

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🚀 Installation

# Run directly with npx (recommended for MCP clients)
npx -y pkinative-mcp

# Or install globally
npm install -g pkinative-mcp
pkinative-mcp

Requirements: Node.js ≥ 22 (the engine's floor is ^22.22.2 || ^24.14.1 || >=25.8.2; describe_engine.capabilities.nodeFloorSatisfied tells you). From source: git clone https://github.com/Nizoka/pkinative-mcp.git && cd pkinative-mcp && npm ci --ignore-scripts && npm run build && node dist/cli.js.

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⚙️ Configuration

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "pkinative": {
      "command": "npx",
      "args": ["-y", "pkinative-mcp"],
      "env": {
        "PKINATIVE_MCP_OUTPUT_DIR": "/Users/you/Documents/mcp-pki"
      }
    }
  }
}

Claude Code

.mcp.json at the root of the project (the repository ships one that drives the built server from dist/cli.js):

{
  "mcpServers": {
    "pkinative": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "pkinative-mcp"],
      "env": { "PKINATIVE_MCP_OUTPUT_DIR": "${CLAUDE_PROJECT_DIR}/.mcp-pki" }
    }
  }
}

Cursor / Continue / Zed / Windsurf / Cline / Roo Code

Any MCP-compatible client that supports stdio servers will work. Use the same command + args + env triple. Example for Cursor (~/.cursor/mcp.json):

{
  "mcpServers": {
    "pkinative": {
      "command": "npx",
      "args": ["-y", "pkinative-mcp"],
      "env": { "PKINATIVE_MCP_OUTPUT_DIR": "/Users/you/Documents/mcp-pki" }
    }
  }
}

Windsurf / Cline / Roo Code use the same shape inside their respective MCP config files.

VS Code

.vscode/mcp.json:

{
  "servers": {
    "pkinative": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "pkinative-mcp"],
      "env": { "PKINATIVE_MCP_OUTPUT_DIR": "${workspaceFolder}/.mcp-pki" }
    }
  }
}

🌐 Supported AI Ecosystem & Clients

pkinative-mcp is designed for MCP-native environments and works with clients that support MCP over stdio or Streamable HTTP: Claude Desktop, Claude Code, Cursor, Continue, Zed, Windsurf, Cline, Roo Code, VS Code, ChatGPT (Streamable HTTP), the MCP Inspector, and any client built on the MCP TypeScript / Python SDKs. Because the server never opens a socket of its own, it is also safe to run inside air-gapped or egress-restricted hosts — which is where PKI material usually lives.

It is the third server of the "native" family, after pdfnative-mcp (PDF) and zipnative-mcp (ZIP): the same thin-wrapper architecture, the same sandbox, cache, projection and governance conventions, the same human-in-the-loop rules. The same engine is on the command line as pkinative-cli.

🔌 MCP protocol compliance

The server is built on the MCP TypeScript SDK v2 (@modelcontextprotocol/server) and speaks MCP 2026-07-28:

• Stateless serving — server/discover replaces the session handshake; every result carries resultType and the _meta serverInfo envelope. Over HTTP, 2026-07-28 clients send Mcp-Method / Mcp-Name headers with each POST /mcp.
• Cache hints — tools/list and prompts/list are public with a 24 h ttlMs, server/discover is public for 1 h, and resources/list / resources/templates/list / resources/read are private with ttlMs: 0 (sandbox files are per-host user data).
• Protocol errors — tools/call with an unknown tool name is a JSON-RPC error (-32602, [UNKNOWN_TOOL] Unknown tool: …) rather than an isError result, and an unknown resource URI is -32602 (Invalid params), as the specification requires; isError: true is reserved for execution failures.
• Automatic legacy fallback — a client that opens with initialize is served through the SDK's legacy path on both stdio and HTTP for every revision the SDK negotiates: 2024-10-07, 2024-11-05, 2025-03-26, 2025-06-18 and 2025-11-25 (legacy) next to 2026-07-28 (modern). Nothing changes for existing hosts.
• HTTP — POST /mcp only; GET / DELETE /mcp answer 405 (no SSE resumability; the server is stateless). Bound to 127.0.0.1 with a Host / Origin guard (foreign values → 403); PKINATIVE_MCP_HTTP_TOKEN adds an opt-in bearer-token gate (401 + WWW-Authenticate without it); bodies above 256 MiB → 413.
• stdio — the frame cap is 256 MiB so a multi-MiB base64 CMS message or PKCS#12 fits in one tools/call; as in every SDK release, a request sent before initialize is dropped without a reply on the legacy path.
• Output schemas — every structuredContent validates against the tool's outputSchema (a 2026-07-28 MUST), including verbosity: 'summary' and fields projections: the read and verdict tools declare projectable schemas (all properties optional, additionalProperties: false kept). Input schemas carry no $schema keyword and no $ref by policy (some hosts forward inputSchema to function-calling APIs that reject unknown keywords). serverInfo carries websiteUrl; the resource template is pkinative://output/{+path}.

The tools/call payload (content, structuredContent, isError) is identical between the 2026-07-28 path and the legacy path; tests/http-modern.test.ts asserts it, and tests/schema-conformance.test.ts validates structuredContent with the SDK's JSON Schema 2020-12 validator.

Client	Transport	Protocol negotiated
Claude Desktop, Cursor, Continue, Zed, Windsurf, Cline	stdio	legacy initialize (2024-xx / 2025-xx) — unchanged
ChatGPT and other Streamable HTTP hosts	HTTP POST /mcp	legacy stateless streamable HTTP — unchanged
MCP 2026-07-28 clients (SDK v2 Client, current MCP Inspector)	stdio / HTTP	server/discover, cache hints, _meta envelope

Compatibility matrix — every negotiated revision, on both transports, with the test that proves it:

Revision	Era	stdio	HTTP POST /mcp	Proven by
2024-10-07	legacy initialize	✓	✓	tests/protocol-revisions.test.ts
2024-11-05	legacy initialize	✓	✓	tests/protocol-revisions.test.ts
2025-03-26	legacy initialize	✓	✓	tests/protocol-revisions.test.ts
2025-06-18	legacy initialize	✓	✓	tests/protocol-revisions.test.ts, tests/http-transport.test.ts
2025-11-25	legacy initialize	✓	✓	tests/protocol-revisions.test.ts, tests/cli-stdio.test.ts, tests/autonomy.test.ts
2026-07-28	modern (server/discover, _meta envelope, cache hints)	✓	✓ (+ bearer token)	tests/stdio-modern.test.ts, tests/http-modern.test.ts, tests/autonomy.test.ts

Environment variables

All nine are declared in server.json, read once at boot; an invalid value (a PKINATIVE_MCP_PORT outside 1–65535, a relative PKINATIVE_MCP_OUTPUT_DIR, a malformed instant or ceiling) refuses to start — never a silent fallback. Only the presence of a secret is logged.

Variable	Default	Meaning
PKINATIVE_MCP_OUTPUT_DIR	(unset)	Absolute path of the one sandbox directory: every path input (PKI objects, content, keys) is read from it and outputMode: 'file' outputs are written under it (exclusive create — never overwritten). The real path of every file read and of every parent written must stay inside it: a symlink or junction planted in the sandbox is SECURITY_VIOLATION on both sides. Key-bearing files (.key .p8 .p12 .pfx) are read by the key tools only, never written, never served as resources — and resources/* refuse key material by content too, whatever the name. Unset ⇒ every tool works on inline PEM / base64 only.
PKINATIVE_MCP_CACHE_DIR	(unset)	Opt-in content-addressed response cache (SHA-256 keyed, 1 h TTL, 256 MiB LRU, plaintext at rest; key namespaced by tool API, package and engine version). Never caches a path input, file output, a call carrying a password or a signer, a 'random' serial or nonce, a 'now' or unpinned instant, describe_engine or draft_governance_issue — nor any password-accepting tool while PKINATIVE_MCP_PASSWORD is set; a hit carries _meta.cached: true.
PKINATIVE_MCP_PORT	(unset → stdio)	When set to a valid port (1–65535), serves Streamable HTTP on http://127.0.0.1:<port>/mcp instead of stdio; any other value refuses to start. Request bodies up to 256 MiB are accepted (413 above). Loopback only, DNS-rebinding protection (foreign Host / Origin → 403), GET / DELETE → 405. No authentication unless PKINATIVE_MCP_HTTP_TOKEN is set — other local processes can reach the endpoint.
PKINATIVE_MCP_HTTP_TOKEN	(unset)	(secret) Opt-in bearer token for the HTTP transport (≥ 16 characters, no whitespace — a weaker value aborts startup). When set, every /mcp request must carry Authorization: Bearer <token>; otherwise 401 + WWW-Authenticate: Bearer realm="pkinative-mcp" (with error="invalid_token" only when credentials were sent — RFC 6750 §3.1). Compared constant-time, never logged.
PKINATIVE_MCP_PASSWORD	(unset)	(secret) The operator-side password of the encrypted PKCS#8 key or PKCS#12 file the tools open — it keeps the secret out of the model transcript. It counts as the password of every password-accepting tool (inspect_private_key, inspect_pkcs12, open_pkcs12, the signer of the signing tools): "describe without a password" needs it unset. Exclusive with the per-call password input (both at once is VALIDATION_ERROR). Never logged; only its presence is reported at startup.
PKINATIVE_MCP_AT	(unset → wall clock)	Pinned instant (ISO 8601, or epoch milliseconds) every omitted at / notBefore / signingTime falls back to, for reproducible verdicts and artefacts. Unset: the wall clock — and a clock-dependent result is never cached.
PKINATIVE_MCP_MAX_INPUT_BYTES	67108864 (64 MiB)	Operator ceiling for limits.maxInputBytes and the decoded size of one PKI object (the engine default). Integer ≥ 1024. A per-call value above it is LIMIT_CEILING_EXCEEDED; a ceiling below the engine default tightens the default silently.
PKINATIVE_MCP_MAX_KDF_ITERATIONS	10000000	Operator ceiling for limits.maxKdfIterations and limits.maxPkcs12KdfIterations (the engine default): the CPU bound of a hostile PBES2 key or PKCS#12 file. Integer ≥ 1.
PKINATIVE_MCP_MAX_PATHS_EXPLORED	1000	Operator ceiling for limits.maxPathsExplored (the engine default): the RFC 5280 §6 path-building work bound. Integer ≥ 1.

The operator ceilings. The engine's 22 named PkiLimits (maxInputBytes, maxDepth, maxNodes, maxIntegerBytes, maxOidBytes, maxBerSegments, maxPemBlocks, maxExtensions, maxGeneralNames, maxNameAttributes, maxPolicies, maxChainLength, maxPolicyNodes, maxRevokedCertificates, maxOcspSingleResponses, maxPathsExplored, maxSignerInfos, maxAttributes, maxCmsCertificatesAndCrls, maxKdfIterations, maxPkcs12Bags, maxPkcs12KdfIterations) can be raised per call through the limits fragment for trusted input only. Three of them are bounded by the three operator ceilings above: a value above the ceiling is refused with LIMIT_CEILING_EXCEEDED and data.env names the variable an operator would raise. There is no "unbounded" and no ceiling a tool argument can move. describe_engine reports the defaults, the ceilings and every cap in force.

---

🛠 Tool reference

Every PKI object input is an object with exactly one of pem (RFC 7468 text), derBase64 (the DER as base64, exactly once — no data: URI, not PEM) or path (relative, inside the sandbox; .pem .crt .cer .der .csr .p10 .crl .p7s .p7b .p7c .p7m .cms .p12 .pfx .key .p8 .pub .ocsp .ors .orq .tsq .tsr .tst .bin .asn1). Every engine-touching tool takes the PARSE fragment (encodingRules, pemMode, strict, limits); the read and verdict tools take verbosity and fields; the artefact tools take outputMode, outputPath and encoding. The fragments are described in Shared input fragments. Error results: content[0].text = "<tool> failed [CODE]: message", isError: true, _meta.error = { code, message, data? }. Full input / output schemas are advertised by tools/list; the consumer contract — catalogue, decision tree, recipes and the complete error table — is docs/AGENT_CONTRACT.md. Every example below is an executable call from examples/ or a tool's _meta.examples (the fixtures/… paths are the TEST-ONLY PKI the examples runner copies into the sandbox; test-only-password is their published password).

convert_pem

The RFC 7468 layer (catalogue). Inputs: mode (decode | encode), input (PKI_INPUT; encode takes exactly one DER value), label, extractIndex, PARSE, PROJECTION, OUTPUT (encoding der / pem / hex). Output: blocks[] (index, label, sizeBytes, offset, sha256), count, extracted, and the artefact when a block is extracted or DER is wrapped. Codes: SECURITY_VIOLATION (a private-key block, or key material anywhere in the input — a key behind a prefix or among other blocks included — under any label), NOT_FOUND (an index past the last block), VALIDATION_ERROR, PKI_PEM_UNEXPECTED_LABEL, PKI_PEM_*.

{ "mode": "decode", "input": { "path": "fixtures/leaf.crt.pem" }, "label": "CERTIFICATE", "extractIndex": 0, "encoding": "hex", "fields": ["extracted", "artefact"] }

resolve_oid

Object identifiers in one call. Inputs: mode (name | validate | list | encode | decode), oids[] (≤ 1000), filter, offset / limit (200 default, 2000 max), form (content | tlv), relative, hex or input (a PKI_INPUT — pem / derBase64 / path — as the decode source), PARSE, PROJECTION. Output: per mode — oids[] with names or validity, entries[] + total / hasMore, or one oid + name. encode answers hex per OID, never an artefact: a PEM-wrapped OID is encode_asn1 { spec: { type: 'oid', value }, encoding: 'pem', label }. Codes: VALIDATION_ERROR (a member outside its mode, relative without form: 'tlv', both hex and input), PKI_OID_INVALID (encode / decode; validate reports it instead), PKI_ASN1_*.

{ "mode": "name", "oids": ["1.2.840.10045.4.3.2", "2.5.29.17", "1.3.6.1.5.5.7.3.1", "1.2.3.4"] }

compute_fingerprint

The digest of one object. Inputs: input (PKI_INPUT, any label or DER; a bundle is refused), mode (fingerprint | key-id | shake256), algorithm, webcrypto, outputLength (≤ 1 MiB), separator, letterCase, PARSE, PROJECTION. Output: hex, formatted, algorithm, sizeBytes, label, from (where the public key came from in key-id). Codes: VALIDATION_ERROR (an algorithm outside its mode, SHA-384 / 512 for a key identifier), PKI_X509_* / PKI_ASN1_* (key-id on an object without a public key).

{ "input": { "path": "fixtures/leaf.csr.pem" }, "mode": "key-id", "fields": ["formatted", "from"] }

decode_asn1

The X.690 node tree. Inputs: input (PKI_INPUT — never a private key or a PKCS#12), sequence, nodePath ('0.2.1'), read (boolean | integer | small-integer | enumerated | null | bit-string | octet-string | oid | relative-oid | string | time), stringType, timeType, reencode, label (the PEM label of a reencode artefact when the input had none or a sub-node is selected), allowTrailingData, maxPreviewBytes (default 32), PARSE, PROJECTION, OUTPUT. Output: nodes[] (path, offset, lengths, tag, constructed, children, preview, oid + oidName), nodeCount, truncated (past 20 000 nodes), value (the typed read), reencode.identical, artefact. Codes: SECURITY_VIOLATION, NOT_FOUND (a missing nodePath step, naming the range), PKI_ASN1_UNEXPECTED_TAG (a wrong reader), PKI_API_MISUSE (an IMPLICIT string / time without stringType / timeType), PKI_ASN1_*, ENGINE_ERROR (the call stack exhausted inside a raised limits.maxDepth — the message names the remedy: lower it).

{ "input": { "path": "fixtures/leaf.crt.der" }, "nodePath": "0.1", "read": "integer", "verbosity": "summary" }

encode_asn1

A JSON node spec to DER. Inputs: spec (one node { type, … }), label (for encoding: 'pem'), PARSE, OUTPUT (encoding der / hex / pem; default der). Output: the artefact (sizeBytes, sha256, hex or the resource) and summary (root tag, node count). Codes: VALIDATION_ERROR naming the JSON path ($.children[1].value …), SECURITY_VIOLATION (a private-key label, or a value that parses as a key or a PKCS#12), PKI_LIMIT_EXCEEDED (nesting past limits.maxDepth), PKI_ASN1_*, PKI_OID_INVALID.

{ "spec": { "type": "sequence", "children": [{ "type": "oid", "value": "1.2.840.10045.4.3.2" }] }, "encoding": "hex" }

inspect_certificate

The RFC 5280 report. Inputs: certificate (PKI_INPUT), extension (one of the 19 kinds), rawExtensions, issuer (PKI_INPUT) or checkSelfSignature, requireAlgorithmMatch, fingerprints[], allowSha1, PARSE, PROJECTION. Output: version, serialNumber, signatureAlgorithm, issuer / subject (+ issuerString / subjectString), validity, subjectPublicKeyInfo, extensions[], selfIssued, fingerprints, signature (valid / algorithm, when checked), diagnostics[]. Codes: NOT_FOUND (an extension the certificate lacks), PKI_PEM_UNEXPECTED_LABEL (a key given as a certificate — refused by label before any byte is parsed), PKI_X509_*, PKI_CRYPTO_ALGORITHM_REFUSED (SHA-1 without allowSha1).

{ "certificate": { "path": "fixtures/leaf.crt.pem" }, "issuer": { "path": "fixtures/inter.crt.pem" }, "fingerprints": ["SHA-256", "SHA-1"], "fields": ["signature", "extensions.kind", "subjectString", "fingerprints"] }

create_certificate

Issue a certificate. Inputs: spec (serialNumber — integer, hex string or 'random', subject, issuer, notBefore, notAfter / validityDays, extensions — basicConstraints, keyUsage, extendedKeyUsage, subjectAltName, issuerAltName, SKI / AKI, raw), issuerCertificate (PKI_INPUT; omitted = self-signed), subjectPublicKey (a certificate, a CSR or a PUBLIC KEY), signer (SIGNER), allowSha1, PARSE, OUTPUT (default pem). Output: the artefact and summary (serialNumber, randomSerial, subject, issuer, selfSigned, signatureAlgorithm, notBefore / notAfter with notBeforeSource, the extension kinds, signatureVerified, publicKeyFrom). Codes: KEY_MISMATCH (the new certificate did not verify against the issuer or itself), RSA_SCHEME_REQUIRED, KEY_TYPE_REQUIRED, SECRET_REQUIRED, UNSUPPORTED_KEY, VALIDATION_ERROR (an unknown spec member, SHA-1 without allowSha1, notAfter before notBefore).

{
  "spec": {
    "serialNumber": 1,
    "subject": { "C": "FR", "O": "Acme", "CN": "Acme Test CA" },
    "notBefore": "2027-01-01T00:00:00Z",
    "validityDays": 3650,
    "extensions": { "basicConstraints": { "ca": true, "pathLen": 0 }, "keyUsage": ["keyCertSign", "cRLSign"] }
  },
  "signer": { "key": { "path": "fixtures/ed25519.key.pem" } }
}

encode_x509_structure

One building block to DER. Inputs: structure (name | name-attribute | validity | spki | algorithm-identifier | attribute | extension | extensions | basic-constraints | key-usage | extended-key-usage | subject-alt-name | subject-key-identifier | authority-key-identifier | signature-algorithm), spec (a closed object), signer (signature-algorithm only — the key is imported non-extractable and only its algorithm is read), label, allowSha1, PARSE, OUTPUT (default hex). Output: the artefact (hex by default) and summary. Codes: VALIDATION_ERROR naming spec <member> (an unknown or missing member is never dropped silently), KEY_TYPE_REQUIRED, SECRET_REQUIRED, RSA_SCHEME_REQUIRED.

{ "structure": "subject-alt-name", "spec": { "dns": ["svc.example.test", "*.wild.example.test"], "ip": ["192.0.2.1"] } }

decode_extension

One extnValue by OID. Inputs: oid, valueHex or value (PKI_INPUT — the DER inside the OCTET STRING), critical, PARSE, PROJECTION. Output: kind, oid, name, critical, sizeBytes, decoded (the kind's members), diagnostics[] (the criticality check). Codes: PKI_X509_EXTENSION_MALFORMED (remedy: decode_asn1), VALIDATION_ERROR.

{ "oid": "2.5.29.19", "valueHex": "30030101ff", "critical": true }

check_certificate_name

The RFC 6125 identity verdict. Inputs: certificate form — certificate (PKI_INPUT) + host or ip, chain[] (PKI_BUNDLE, for the CN fallback), allowCommonNameFallback (default false), allowWildcards (default true); match form — presented + reference; PARSE, PROJECTION. Output: form, valid, reasons[], reference, subject / presented, match. Codes: PKI_REASON_NAME_MISMATCH and friends in reasons[] (a verdict, never isError); VALIDATION_ERROR (both forms at once).

{ "certificate": { "path": "fixtures/leaf.crt.pem" }, "host": "a.wild.example.test", "verbosity": "summary" }

check_certificate_purpose

The RFC 5280 §4.2.1.12 purpose verdict. Inputs: certificate, chain[] (leaf's issuer first), purpose (serverAuth | clientAuth | codeSigning | emailProtection | timeStamping | ocspSigning | any | a dotted OID), restrictIssuers (default true), requireExplicitPurpose (default false), PARSE, PROJECTION. Output: valid, reasons[], purposeOid, purposeName, subject, pathLength. Codes: PKI_REASON_PURPOSE_NOT_PERMITTED (with the path[i] element) in reasons[]; VALIDATION_ERROR (an unknown purpose name).

{ "certificate": { "path": "fixtures/leaf.crt.pem" }, "purpose": "codeSigning" }

inspect_csr

The RFC 2986 report. Inputs: request (PKI_INPUT), rawExtensions, verify (default true — the proof of possession, one Web Crypto verification), allowSha1, PARSE, PROJECTION. Output: subject (+ subjectString), subjectPublicKeyInfo, attributes[], extensions[], challengePassword (present or not, never its text), signatureAlgorithm, signature (valid, reasons[]). Codes: PKI_REASON_SIGNATURE_NOT_CHECKED in signature.reasons[] (SHA-1 without allowSha1), PKI_X509_*, PKI_PEM_UNEXPECTED_LABEL.

{ "request": { "path": "fixtures/leaf.csr.pem" }, "verbosity": "summary" }

create_csr

A PKCS#10 request. Inputs: spec (subject, extensions — subjectAltName, keyUsage, extendedKeyUsage, basicConstraints, subjectKeyIdentifier, raw; the issuer's extensions are refused), subjectPublicKey (required for an encrypted PKCS#8 key), signer (SIGNER), allowSha1, PARSE, OUTPUT (default pem). Output: the artefact and summary (subject, signatureAlgorithm, the requested extension kinds, signatureVerified, publicKeyFrom). Codes: KEY_MISMATCH (the key does not match the public key named), RSA_SCHEME_REQUIRED, SECRET_REQUIRED, KEY_TYPE_REQUIRED, VALIDATION_ERROR.

{
  "spec": {
    "subject": { "C": "FR", "O": "Acme", "CN": "svc.example.test" },
    "extensions": { "subjectAltName": { "dns": ["svc.example.test", "www.svc.example.test"] }, "keyUsage": ["digitalSignature"], "extendedKeyUsage": ["serverAuth"] }
  },
  "signer": { "key": { "path": "fixtures/leaf.key.pem" } }
}

verify_certificate_chain

The RFC 5280 §6 verdict. Inputs: leaf (PKI_INPUT), TRUST (trustAnchors[], candidates[], crls[], ocspResponses[], at, requireRevocation, purposes[], policy), serverName (host | ip), ocspNonce, requireOcspNonce, allowSha1, PARSE, PROJECTION. Output: valid, reasons[], path[] (leaf first up to the anchor), pathLength, explored, signatureVerifications[], evaluatedAt + evaluatedAtSource, revocationEvidence. Codes: PKI_REASON_* in reasons[] — NO_TRUST_ANCHOR, EXPIRED, NOT_YET_VALID, REVOKED, REVOCATION_UNKNOWN, REVOCATION_STALE, NAME_MISMATCH, PURPOSE_NOT_PERMITTED, … (a verdict, never isError); VALIDATION_ERROR, PKI_* for inputs the engine refuses.

{
  "leaf": { "path": "fixtures/revoked.crt.pem" },
  "candidates": [{ "path": "fixtures/inter.crt.pem" }],
  "trustAnchors": [{ "path": "fixtures/root.crt.pem" }],
  "crls": [{ "path": "fixtures/inter.crl.pem" }],
  "ocspResponses": [{ "path": "fixtures/revoked.ocsp.der" }],
  "requireRevocation": true,
  "at": "2027-01-01T00:00:00Z",
  "fields": ["valid", "reasons.code", "revocationEvidence", "pathLength"]
}

build_certificate_path

Path discovery, signatures not checked. Inputs: leaf, candidates[], trustAnchors[], at, purposes[], policy, PARSE, PROJECTION. Output: found, structuralReasons[], path[], pathLength, explored, valid (always false), reasons[], signaturesChecked: false. Codes: PKI_REASON_SIGNATURE_NOT_CHECKED (always present), PKI_REASON_NO_TRUST_ANCHOR (in structuralReasons[] when no path reached an anchor).

{ "leaf": { "path": "fixtures/leaf.crt.pem" }, "candidates": [{ "path": "fixtures/inter.crt.pem" }], "trustAnchors": [{ "path": "fixtures/root.crt.pem" }], "at": "2027-01-01T00:00:00Z", "verbosity": "summary" }

validate_certificate_path

RFC 5280 §6.1 on an ordered path. Inputs: path[] (PKI_BUNDLE, leaf first), trustAnchors[], at, checkSignatures (default true), policy, allowSha1, PARSE, PROJECTION. Output: valid, reasons[], failingReasons[], path[], signaturesChecked, signatures[] (one verdict per link), evaluatedAt. Codes: PKI_REASON_SIGNATURE_INVALID, PKI_REASON_SIGNATURE_NOT_CHECKED (checkSignatures: false), VALIDATION_ERROR.

{ "path": [{ "path": "fixtures/leaf.crt.pem" }, { "path": "fixtures/inter.crt.pem" }], "trustAnchors": [{ "path": "fixtures/root.crt.pem" }], "at": "2027-01-01T00:00:00Z" }

inspect_crl

The RFC 5280 §5 report. Inputs: crl (PKI_INPUT), find (serialHex | certificate), issuer (PKI_INPUT, one signature check), allowSha1, PARSE, PROJECTION. Output: issuer (+ issuerString), signatureAlgorithm, thisUpdate / nextUpdate, crlNumber, isDelta, baseCrlNumber, issuingDistributionPoint, entryCount, extensions[], entry (revoked, revocationDate, reason, invalidityDate), signature. Codes: VALIDATION_ERROR, PKI_X509_*, PKI_CRYPTO_ALGORITHM_REFUSED.

{ "crl": { "path": "fixtures/inter.crl.der" }, "find": { "certificate": { "path": "fixtures/revoked.crt.pem" } }, "fields": ["entry", "issuerString", "crlNumber", "nextUpdate.iso"] }

check_crl_revocation

One certificate against one CRL. Inputs: certificate, crl, delta, issuer (the CRL issuer — without it the list is not accepted as evidence: valid: false with PKI_REASON_REVOCATION_UNKNOWN, a verdict), at, staleTolerance (ms), allowSha1, PARSE, PROJECTION. Output: valid, reasons[], signatureVerified, deltaSignatureVerified, crlNumber, isDelta, deltaCrlNumber, evaluatedAt. A delta whose signature does not verify against issuer is not applied: valid: false with PKI_REASON_REVOCATION_UNKNOWN on delta. Codes: PKI_REASON_REVOKED (with the reason), PKI_REASON_REVOCATION_UNKNOWN and the freshness / scope reasons in reasons[]; VALIDATION_ERROR (a delta without a deltaCRLIndicator).

{ "certificate": { "path": "fixtures/ed25519.crt.pem" }, "crl": { "path": "fixtures/ed25519.crl.der" }, "delta": { "path": "fixtures/ed25519-delta.crl.der" }, "issuer": { "path": "fixtures/ed25519.crt.pem" }, "at": "2027-01-01T00:00:00Z" }

create_ocsp_request

The RFC 6960 request you POST yourself. Inputs: certificate, issuer, hashAlgorithm (SHA-1 default | SHA-256), nonce ('random' or 1–32 bytes of hex), certIdOnly, label (the PEM label for encoding: 'pem'), PARSE, OUTPUT (default der, .orq). Output: the artefact and summary (certIdHex, nonceHex, randomNonce, serial). Codes: VALIDATION_ERROR.

{ "certificate": { "path": "fixtures/leaf.crt.pem" }, "issuer": { "path": "fixtures/inter.crt.pem" }, "hashAlgorithm": "SHA-256", "nonce": "random", "encoding": "hex" }

inspect_ocsp_response

The RFC 6960 report. Inputs: response (PKI_INPUT), responder (PKI_INPUT, one signature check; omitted = the embedded certificates are tried), PARSE, PROJECTION. Output: status, basicResponse (responder id, producedAt, responses[] with CertID / status / updates, extensions, certificates, signature algorithm), noncePresent, signature (valid, source). Codes: PKI_ASN1_*, PKI_X509_*, VALIDATION_ERROR.

{ "response": { "path": "fixtures/revoked.ocsp.der" }, "responder": { "path": "fixtures/ocsp.crt.pem" }, "fields": ["signature", "basicResponse.responses.status", "basicResponse.responses.certId.serialNumber", "noncePresent"] }

check_ocsp_status

One response for one certificate. Inputs: response, certificate, issuer, responder, responderTrusted, hashAlgorithm, nonce (hex), requireNonce, at, staleTolerance, futureTolerance, allowSha1, PARSE, PROJECTION. Output: valid, reasons[], status (good | revoked | unknown | null), signatureVerified, responderAuthorized, responder, responderSource, hashAlgorithm, certIdHex, evaluatedAt. Codes: PKI_REASON_REVOKED, the freshness, nonce and authorisation reasons in reasons[] (a non-successful response status is a negative verdict with status: null); VALIDATION_ERROR.

{ "response": { "path": "fixtures/leaf.ocsp.der" }, "certificate": { "path": "fixtures/leaf.crt.pem" }, "issuer": { "path": "fixtures/inter.crt.pem" }, "nonce": "1538349c433373ed058c291909df5b3e", "requireNonce": true, "at": "2027-01-01T00:00:00Z", "verbosity": "summary" }

sign_cms

An RFC 5652 SignedData. Inputs: content (CONTENT_INPUT) or contentDigest (HEX, detached only), detached, contentType (OID), certificate, chain[], crls[], sid (issuerAndSerialNumber default | subjectKeyIdentifier), signingTime (an instant, 'now', 'none'), signingCertificateV2, algorithmProtection, signedAttributes[] / unsignedAttributes[] (DER Attributes as hex), signer (SIGNER), allowSha1, PARSE, OUTPUT (default der, .p7s). Output: the artefact and summary (detached, contentType, signerSubject / signerSerial, sid, digest and signature algorithms, signingTime with signingTimeSource, certificatesEmbedded, crlsEmbedded, attribute counts, signatureVerified). Codes: KEY_MISMATCH (the new signature did not verify against the signer certificate), RSA_SCHEME_REQUIRED, SECRET_REQUIRED, KEY_TYPE_REQUIRED, VALIDATION_ERROR (contentDigest without detached, certificate missing with signer.key), SECURITY_VIOLATION (a content.path naming a key-bearing extension or holding key material — the content a tool reads from the sandbox is never a key), PKI_API_MISUSE (a repeated or builder-owned attribute type), ENGINE_ERROR.

{
  "content": { "path": "fixtures/content.txt" },
  "detached": true,
  "certificate": { "path": "fixtures/leaf.crt.pem" },
  "chain": [{ "path": "fixtures/inter.crt.pem" }],
  "signingTime": "2027-01-01T00:00:00Z",
  "signer": { "key": { "path": "fixtures/leaf.key.pem" } }
}

verify_cms

The RFC 5652 verdict. Inputs: signedData (PKI_INPUT), content (CONTENT_INPUT) or contentDigest (detached signatures), TRUST (trustAnchors[], candidates[], crls[], ocspResponses[], at, requireRevocation, purposes[]), atTimeStamp, requireSigningCertificate, requireAlgorithmProtection, allowTrailingData, allowSha1, PARSE, PROJECTION. Output: valid, reasons[], signers[] (per signer: valid, intact, reasons[], chain, time-stamps, revocation), signerCount, signatureVerifications[], evaluatedAt, atTimeStamp. Codes: PKI_REASON_* in reasons[] (NO_TRUST_ANCHOR, SIGNATURE_INVALID, REVOKED, TSP_*, …); PKI_API_MISUSE (content given for an attached message — it carries its own), VALIDATION_ERROR (both content and contentDigest), PKI_ASN1_TRAILING_DATA (the zero padding of a PDF /Contents without allowTrailingData).

{ "signedData": { "path": "fixtures/attached.p7s" }, "trustAnchors": [{ "path": "fixtures/root.crt.pem" }], "crls": [{ "path": "fixtures/inter.crl.pem" }], "ocspResponses": [{ "path": "fixtures/leaf.ocsp.der" }], "requireRevocation": true, "purposes": ["emailProtection"], "at": "2027-01-01T00:00:00Z" }

inspect_cms

The RFC 5652 report. Inputs: signedData, allowTrailingData, signerCertificate (one key check), signerIndex, content (for a signer without signed attributes), allowSha1, PARSE, PROJECTION. Output: version, contentType, contentLength (null = detached), digestAlgorithms[], certificates[], crlCount, ocspResponseCount, signerInfos[] (sid, algorithms, signing time as claimed, attributes, time-stamp count, signature as hex), signerSignature. Codes: NOT_FOUND (a signerIndex past the last signer, when signerCertificate is given — the index names the signer that check applies to), PKI_ASN1_TRAILING_DATA, PKI_*.

{ "signedData": { "path": "fixtures/detached.p7s" }, "signerCertificate": { "path": "fixtures/leaf.crt.pem" }, "content": { "path": "fixtures/content.txt" }, "fields": ["signerInfos.signature", "signerInfos.sid", "signerSignature"] }

amend_cms

The one legitimate edit. Inputs: signedData, signerIndex, operation (add-unsigned-attribute | add-timestamp), attribute (HEX), token (PKI_INPUT — a .tst or a whole .tsr), allowSha1, PARSE, OUTPUT (default der). Output: the artefact and summary. Codes: VALIDATION_ERROR with data.detail PKI_REASON_TSP_IMPRINT_MISMATCH (a token over anything but the signer's signature value — the remedy names the inspect_cms → create_timestamp_request → amend_cms sequence), NOT_FOUND, PKI_API_MISUSE (a signed-only attribute type), PKI_*.

{ "signedData": { "path": "fixtures/attached.p7s" }, "operation": "add-unsigned-attribute", "attribute": "300d06032a0304310606042a030405" }

create_timestamp_request

The RFC 3161 request you POST yourself. Inputs: data (CONTENT_INPUT) or digestHex (HEX), hashAlgorithm (SHA-256 default | SHA-384 | SHA-512), nonce ('random', decimal or 0x hex), policy (OID), certReq (default true), label (the PEM label for encoding: 'pem'), PARSE, OUTPUT (default der, .tsq). Output: the artefact and summary (imprintHex, hashAlgorithm, nonce, randomNonce, policy, certReq). Codes: VALIDATION_ERROR (a digest whose length does not match the algorithm), SECURITY_VIOLATION (a data.path naming a key-bearing extension or holding key material).

{ "data": { "path": "fixtures/content.txt" }, "nonce": "random" }

inspect_timestamp

The RFC 3161 report. Inputs: input (PKI_INPUT), as (response | token | tstinfo), PARSE, PROJECTION. Output: as, status (statusStrings, failInfo), token (CMS envelope: signer count, certificates), tstInfo (policy, messageImprint, serialNumber, genTime, accuracy, ordering, nonce, tsa, extensions). Codes: PKI_* (the bytes are none of the three structures), PKI_STRICT_DIAGNOSTIC (with strict: true — OpenSSL tokens carry PKI_DIAG_CMS_SET_NOT_SORTED).

{ "input": { "path": "fixtures/content.tst" }, "as": "token", "fields": ["token.tstInfo.genTime.iso", "token.tstInfo.messageImprint", "token.certificates.subject"] }

verify_timestamp

The RFC 3161 verdict. Inputs: token or response, request (the .tsq you sent — imprint, nonce and policy all checked), data (CONTENT_INPUT) or digestHex, TRUST (trustAnchors[], candidates[], crls[], ocspResponses[], at, requireRevocation), allowNonCriticalTimeStampingEku, allowSha1, PARSE, PROJECTION. Output: valid, reasons[], genTime, earliest / latest (accuracy applied), tsa, chain ({ valid, path[], reasons[] }), signatureVerifications[], evaluatedAt. Codes: PKI_REASON_TSP_IMPRINT_MISMATCH, PKI_REASON_TSP_NOT_GRANTED, PKI_REASON_TSP_REQUEST_MISMATCH, PKI_REASON_TSP_TOKEN_INVALID and the chain reasons in reasons[]; VALIDATION_ERROR (nothing stamped was given — a token verified without what it stamps proves nothing).

{ "response": { "path": "fixtures/content.tsr" }, "request": { "path": "fixtures/content.tsq" }, "data": { "path": "fixtures/content.txt" }, "trustAnchors": [{ "path": "fixtures/root.crt.pem" }], "candidates": [{ "path": "fixtures/inter.crt.pem" }], "at": "2027-01-01T00:00:00Z" }

inspect_private_key

A PKCS#8 key described, no key byte. Inputs: key (PKI_INPUT), tryImport, password (or PKINATIVE_MCP_PASSWORD), keyType (ec-p256 | ec-p384 | ec-p521 | ed25519 | ed448 | rsa | rsa-pss), hash, rsaScheme, saltLength, allowSha1, PARSE, PROJECTION. Output: format (pkcs8 | encrypted-pkcs8), kind, curve, algorithm + algorithmName, attributes, publicKey (embedded or not), encryption (scheme, PBKDF2 iterations, PRF, AES key size, salt length), encryptedBytes, imported (handle type, algorithm, usages). Codes: SECRET_REQUIRED, KEY_TYPE_REQUIRED, RSA_SCHEME_REQUIRED, PKI_CRYPTO_DECRYPTION_FAILED (a wrong password), PKI_KEY_ENCRYPTION_UNSUPPORTED (a legacy cipher, with the openssl pkcs8 remedy), PKI_* (a PUBLIC KEY or a non-PKCS#8 DER).

{ "key": { "path": "fixtures/leaf.key.enc.pem" }, "tryImport": true, "password": "test-only-password", "keyType": "ec-p256", "fields": ["imported", "encryption.scheme"] }

inspect_pkcs12

A PKCS#12 described, no key byte. Inputs: pkcs12 (PKI_INPUT; BER with encodingRules: 'ber' for a Windows-written PFX), password (optional), PARSE, PROJECTION. Output: version, mac (kind pbmac1 | pkcs12-kdf | null, parameters), contents[] (path, encryption scheme and parameters, bags of the plain ones), bagCount, macVerified (with a password; false is a report only when no SafeContents is encrypted — otherwise a wrong password is PKI_CRYPTO_DECRYPTION_FAILED before the MAC is reported), opened[] (allow-list views: certBags by subject / issuer / serial, key bags by algorithm, curve and encryption parameters, crlBags by size). A set PKINATIVE_MCP_PASSWORD counts as the password: describing a file without one needs the variable unset. Codes: PKI_CRYPTO_DECRYPTION_FAILED (a wrong password on an encrypted SafeContents), PKI_KEY_MAC_UNSUPPORTED, PKI_KEY_ENCRYPTION_UNSUPPORTED (each with the OpenSSL 3.4 conversion remedy).

{ "pkcs12": { "path": "fixtures/legacy.p12" }, "fields": ["mac.kind", "contents.path", "contents.encryption.scheme"] }

open_pkcs12

A PKCS#12 opened in one call. Inputs: pkcs12, password (or PKINATIVE_MCP_PASSWORD), allowUnverifiedIntegrity, rsaScheme (pkcs1 | pss), hash, exportCertificates, PARSE, PROJECTION, OUTPUT (pem only — a bundle has no DER form). Output: valid, integrity (verified | unverified | mismatch), reasons[], keys[] (algorithm, handle type, usages — never a byte), certificates[], keyCount / certificateCount / crlCount, exportSkipped, artefact (the PEM bundle). Codes: SECRET_REQUIRED (no password from either channel); in reasons[]: PKI_REASON_PKCS12_MAC_MISMATCH (a wrong password or an altered file — nothing is decrypted), PKI_REASON_PKCS12_ENCRYPTION_UNSUPPORTED, PKI_REASON_PKCS12_INTEGRITY_UNVERIFIED, PKI_REASON_PKCS12_RSA_SCHEME_UNSPECIFIED; MISSING_OUTPUT_PATH, OUTPUT_TOO_LARGE.

{ "pkcs12": { "path": "fixtures/leaf.p12" }, "password": "test-only-password", "exportCertificates": true }

describe_engine

The offline preflight. Inputs: PROJECTION only. Output: server (name, version, toolApiVersion, protocol, toolCount), engine (name, version, nodeFloor), capabilities (canVerify, canSign, canDecrypt, node, nodeFloorSatisfied, platform), randomness, defaultLimits, ceilings, caps, sandbox (enabled, cacheEnabled, pinnedInstant, the extension allow-lists), network: 'none', registries (the 57 / 43 / 97 codes, the wrapper codes, purposes, key-usage bits, the OID registry count), refusals (the doctrine), unexposed. Codes: VALIDATION_ERROR.

{ "fields": ["defaultLimits", "ceilings", "sandbox", "capabilities"] }

explain_code

Any code, explained. Inputs: code, or list: true with kind (error | reason | diagnostic | wrapper), PROJECTION. Output: code, kind, summary, standard, severity, errorClass, engineClass, cwe, since, remedy — or codes[] + count. Codes: NOT_FOUND (an unknown code).

{ "code": "PKI_REASON_PKCS12_RSA_SCHEME_UNSPECIFIED" }

draft_governance_issue

Draft a governance-compliant GitHub issue locally for a human to review and submit — for pkinative (engine behaviour: parsing, verification, limits, refusals), pkinative-cli or pkinative-mcp (wrapper behaviour: schemas, sandbox, transport). The server never contacts GitHub — it has no network code path at all; it returns the draft Markdown plus a machine-readable compliance report. Present both to the user, then STOP: they review and submit under their own identity. Inputs: title, summary, issueType (bug | feature | security | docs | performance), targetRepo, reproduction ({ command, result }), expectedBehavior, actualBehavior, affectedPackages[], duplicateSearchPerformed (must be true), outputMode (inline | file) + outputPath (a relative .md in the sandbox). Output: draftMarkdown, warnings[], compliance (the nine keys of .github/AGENT_RULES.md). Codes: GOVERNANCE_VIOLATION (a runtime dependency proposed, an embedded private key or password, no reproduction, duplicateSearchPerformed: false), MISSING_OUTPUT_PATH, INVALID_EXTENSION, OUTPUT_EXISTS, SECURITY_VIOLATION.

{
  "title": "parseCertificateList refuses a delta CRL with an empty revokedCertificates list",
  "summary": "A delta CRL (deltaCRLIndicator present) whose revokedCertificates SEQUENCE is absent is refused with PKI_X509_STRUCTURE_INVALID although RFC 5280 makes the field OPTIONAL.",
  "issueType": "bug",
  "targetRepo": "pkinative",
  "reproduction": { "command": "inspect_crl { crl: { path: \"fixtures/empty-delta.crl\" } }", "result": "PKI_X509_STRUCTURE_INVALID at revokedCertificates" },
  "expectedBehavior": "The delta CRL parses with entryCount 0.",
  "affectedPackages": ["pkinative", "pkinative-mcp"],
  "duplicateSearchPerformed": true
}

See the governance_contract and draft_issue_workflow prompts and docs/guides/AI_GOVERNANCE.md for the full human-in-the-loop contract.

---

🧩 Shared input fragments

The same ten fragments appear across the catalogue; a tool's description names the ones it carries. Every object schema is closed (additionalProperties: false, Zod .strict() at every depth): an unknown or misspelt key is VALIDATION_ERROR naming the path, never silently dropped.

Fragment	Shape	Rules
PKI_INPUT	{ pem } | { derBase64 } | { path }	Exactly one. pem is RFC 7468 text starting with -----BEGIN (a PEM text holding several blocks where one object is expected is refused — use convert_pem extractIndex or a bundle); derBase64 is the DER as base64 exactly once (no data: URI, not PEM); path is relative to the sandbox, PEM or DER sniffed by its first bytes, extension allow-listed, never cached. The label is checked before any byte is parsed (PKI_PEM_UNEXPECTED_LABEL).
PKI_BUNDLE	PKI_INPUT[] (1–256 items)	trustAnchors, candidates, crls, ocspResponses, chain, path: every PEM block of every item is taken, in order.
CONTENT_INPUT	{ text } | { base64 } | { path }	The bytes to sign, verify or time-stamp: UTF-8 text, base64 (≤ 128 MiB decoded) or a sandbox file (any extension but a key-bearing one, ≤ 1 GiB — it is content, not a PKI object; a file holding key material is SECURITY_VIOLATION, since content a tool reads is never a key).
HEX	string	contentDigest, digestHex, valueHex, attribute, nonce, ocspNonce, serialHex: hexadecimal; an 0x prefix, colons and spaces are tolerated (^(?:0x)?(?:[0-9a-fA-F]{2}[:\s]?)+$).
PARSE	encodingRules, pemMode, strict, limits	encodingRules 'der' (strict X.690, default) or 'ber' (indefinite / non-minimal lengths, as legacy CMS producers write); pemMode 'strict' (RFC 7468 exactly) or 'lax' (whitespace, line length, RFC 1421 headers); strict: true escalates the first engine warning to PKI_STRICT_DIAGNOSTIC; limits below.
LIMITS	{ maxInputBytes, maxDepth, … } (the 22 keys)	Raise the engine's named bounds for this call, trusted input only; absent keys keep the engine defaults; every value is an integer ≥ 1; maxInputBytes, maxKdfIterations / maxPkcs12KdfIterations and maxPathsExplored are bounded by the operator ceilings (LIMIT_CEILING_EXCEEDED); a call stack exhausted inside a raised maxDepth is a coded ENGINE_ERROR naming the remedy (lower it).
SIGNER	{ key } | { p12 }, + password, keyType, hash, rsaScheme, saltLength	Exactly one of key (a PKCS#8 private key, plain or PBES2-encrypted, PEM or DER — SEC1 / PKCS#1 keys must be converted with openssl pkcs8 -topk8 first) or p12 (PBES2 + PBMAC1 only). The key is imported into a non-extractable Web Crypto key and never leaves the engine. The algorithm follows the key: ECDSA on the key's curve (SHA-256 / 384 / 512 by curve), Ed25519 / Ed448 (no hash), RSA requires rsaScheme ('pkcs1' | 'pss', optional saltLength); an encrypted key needs password (or PKINATIVE_MCP_PASSWORD) and keyType unless a certificate or public key input names it. A call carrying a signer is never cached.
TRUST	trustAnchors, candidates, crls, ocspResponses, at, requireRevocation, purposes, policy	A verdict is relative to the anchors you name (at least one). at is an ISO 8601 date-time (UTC unless zoned), epoch milliseconds, or 'now'; omitted = PKINATIVE_MCP_AT, else the wall clock (never cached). requireRevocation: true demands fresh evidence for the end-entity certificate (PKI_REASON_REVOCATION_UNKNOWN otherwise — the engine's rule; an intermediate is judged from the evidence you pass, its status reported in revocationEvidence). purposes (≤ 16) are EKU names or OIDs; policy holds the RFC 5280 §6.1.1 inputs (initialPolicySet, requireExplicitPolicy, inhibitPolicyMapping, inhibitAnyPolicy).
PROJECTION	verbosity, fields	'full' (default) or 'summary'; up to 16 dot-paths kept after verbosity (arrays map over elements); every path that matched nothing, nested ones included, is reported in _meta.unmatchedFields with _meta.availableFields; a __proto__ / constructor / prototype segment is VALIDATION_ERROR.
OUTPUT	outputMode, outputPath, encoding	'base64' (default, ≤ 50 MiB inline) or 'file' (a relative outputPath whose extension matches the encoding — .pem for pem; .der .crt .cer .csr .p10 .crl .p7s .p7m .p7b .cms .orq .tsq .bin .asn1 … for der; key-bearing extensions refused; never overwritten; ≤ 1 GiB). encoding 'pem', 'der' or 'hex' (inline only, ≤ 64 KiB; the hex lands in structuredContent.hex).

Every result also carries diagnostics[] (de-duplicated by code and path, capped at 200 with diagnosticsTruncated) and diagnosticCounts; the password input, when a tool has one, is a plain string (≤ 4096 characters) that is never echoed, logged or cached.

---

🔐 Security model

pkinative-mcp runs inside the host process and exposes a stdio MCP server (or a loopback-only HTTP endpoint). It treats every certificate, request, list, response, message, token, key and PKCS#12 as untrusted input and performs no I/O outside the configured sandbox other than the opt-in response cache under PKINATIVE_MCP_CACHE_DIR.

• Secrets: two channels, never a third. A password reaches the server through the per-call password input or the operator-side PKINATIVE_MCP_PASSWORD — one source per call (both at once is VALIDATION_ERROR); SECRET_REQUIRED when neither is present. A password is never echoed in a result or an error text, never logged (only the presence of the variable is reported at boot), never written to a cache file, never served as a resource. Private keys are imported into non-extractable Web Crypto handles; every key and PKCS#12 report is an allow-list view built field by field (src/key-views.ts), and the test suite proves with a needle table computed from the fixtures that no key byte, scalar, JWK member, encrypted-key body or password is printed by any result, on stderr, in a cache file or on the stdio transcript (tests/secret-leak.test.ts).
• The sandbox (PKINATIVE_MCP_OUTPUT_DIR) is the one filesystem boundary for reads (every path input, resources/read) and writes (outputPath, governance drafts). Paths must be relative; absolute / drive / UNC paths, .., NUL bytes and non-allow-listed extensions are rejected; the real path of the file read and of the parent written must stay inside (a symlink or junction planted in the sandbox is SECURITY_VIOLATION on both sides); files are opened exclusively (OUTPUT_EXISTS — never overwritten); a failed write removes the partial file. Key-bearing extensions (.key .p8 .p12 .pfx) are read by the key tools only, never written, never listed nor served by resources/* — and resources/list / resources/read refuse key material by content as well, whatever the file name: a PEM key after a prefix, a key hidden among many blocks, a raw DER key behind junk or base64 key material inside a text file is SECURITY_VIOLATION. The same content test guards the generic encoders (convert_pem encode takes exactly one DER value and refuses key material) and the content inputs (content.path of sign_cms, data.path of create_timestamp_request): what a tool reads from the sandbox as content is never a key. Unset ⇒ inline PEM / base64 only.
• Caps — every byte and count bound is a constant in src/caps.ts and advertised by describe_engine.caps:

Cap	Value
stdio frame / HTTP body	256 MiB
decoded inline PKI inputs per call / inline content	128 MiB / 128 MiB
content.path read fully into memory	1 GiB
inline output (an artefact, a resource read)	50 MiB
file output	1 GiB
inline hex artefact	64 KiB
bundle items / DER attributes inline / OIDs per call	256 / 256 / 1000
resolve_oid list page	200 default / 2000 max
SHAKE256 output / password / fields paths / decode_asn1 preview / tree nodes	1 MiB / 4096 / 16 / 32 bytes / 20 000
diagnostics per result	200 (de-duplicated by code and path)
resources/list entries / walk depth / resources/read	1000 / 8 / 50 MiB
response cache TTL / size	3600 s / 256 MiB
engine defaults (limits)	the 22 PkiLimits of pkinative 1.0.0 — maxInputBytes 64 MiB, maxKdfIterations 10 000 000, maxPathsExplored 1000, … (describe_engine.defaultLimits)

• The cache gate (isCacheable, src/server.ts) — with PKINATIVE_MCP_CACHE_DIR set, a result is served from the cache only when nothing about it depends on the environment, a secret, the clock or randomness: never a path input (a path is a reference, not content), never outputMode: 'file', never a call carrying a password or a signer, never a 'random' serial or nonce, never a 'now' or unpinned instant, never describe_engine or draft_governance_issue, and never any password-accepting tool while PKINATIVE_MCP_PASSWORD is set (the operator password may have been used without any secret in the input). The key namespace carries the tool API, package and engine versions, so an engine upgrade never serves bytes the previous engine wrote.
• Doctrine refusals (describe_engine.refusals) — the lines the server will not cross, each with its remedy: no network, no key generation (bring keys from your HSM, KMS or openssl genpkey), no key export, no writer for PKCS#8 / PKCS#12 / CRL / OCSP response / time-stamp response (use the issuing software or OpenSSL and verify the result here), SHA-1 refused by default, no default RSA scheme, legacy PKCS#12 and PBES1 keys refused (convert once with OpenSSL 3.4+: openssl pkcs12 -legacy … then -export -pbmac1_pbkdf2), DSA / ML-DSA parsed but never verified or signed, diagnostics are not errors, limits raise only explicitly and under the ceilings, randomness lives in the wrapper and is reported (randomSerial, randomNonce).
• Inputs are validated against strict JSON Schemas + Zod at the boundary of every tool — unknown or misspelt keys at any depth are VALIDATION_ERROR; base64 is sanity-checked (data: URIs, PEM where DER is expected, double-encoded or empty payloads refused with a remedy) before any parser runs; specs are built prototype-pollution-safe (tests/prototype-pollution.test.ts).
• HTTP transport (PKINATIVE_MCP_PORT) binds loopback only with a Host / Origin guard; it has no authentication unless PKINATIVE_MCP_HTTP_TOKEN is set (then 401 without a valid bearer token).

Network & egress: none

None, ever. The server has no network code path: no CRL, OCSP, AIA or TSA fetch, no telemetry, no GitHub, no update check, no URL from any tool argument, and — unlike its PDF sibling — no operator-configurable endpoint of any kind. describe_engine reports network: 'none' and every tool advertises openWorldHint: false. Revocation evidence and time-stamp tokens are inputs you fetched out of band; create_ocsp_request and create_timestamp_request produce the bytes you transport (application/ocsp-request, application/timestamp-query). The engine itself never opens a socket, never touches the filesystem and never evals.

See SECURITY.md for the responsible disclosure process and the threat model, and docs/guides/SECURITY.md for the defences with their CWE ids.

---

🧪 Conformance (OpenSSL 3)

OpenSSL 3.x is the external judge of this server — the role veraPDF plays for pdfnative-mcp: what the tools write, a foreign implementation must read and verify. npm run corpus:pki drives the built server (scripts/generate-pki-corpus.ts, corpus table in scripts/lib/pki-corpus.ts) under a pinned instant to write the interoperability corpus into test-output/pki/ with a manifest.json (status, SHA-256, the second digest of every deterministic entry): 23 conformant artefacts — self-signed CAs and leaves for every signature family (Ed25519, RSA PKCS#1 v1.5, RSA-PSS, ECDSA P-256), a pathLen-0 intermediate and a leaf under it, three CSRs, attached and detached CMS messages (the Ed25519 signer included), two time-stamp requests, two OCSP requests, PEM re-encodings of the DER fixtures — and 5 refused canaries that must be refused with their declared code (a SHA-1 signature, a legacy PKCS#12 signer, an RSA key without a scheme, a notAfter before notBefore, a URL member in a spec). A canary that writes bytes is an XPASS and fails the run.

npm run validate:pki (scripts/validate-pki.ts) then checks every artefact at two levels:

• Level 0 — engine round trip, in-process through dist/server.js: every certificate inspected and verified to the corpus CA at the pinned instant (verify_certificate_chain with serverName and purposes for the leaves), every request read with its proof of possession, every CMS message verified with the anchors (and the detached content), every OCSP and time-stamp request decoded and recomputed independently with node:crypto (CertID hashes, serial, message imprint, nonce), and every deterministic entry produced twice hashing the same. It needs no external tool and always runs.
• Level 1 — OpenSSL, openssl 3.x on PATH (OPENSSL_BIN overrides; LibreSSL and OpenSSL < 3.0 are refused with the reason): 12 command families — x509 -text over every certificate (DER and PEM), verify to each corpus CA (-purpose sslserver for the leaves, -untrusted for the intermediate, -attime the pinned instant), req -verify, crl -text, cms -verify (attached and detached, -CAfile the fixture root), asn1parse, ocsp -req_text, ts -query -text — with the raw transcripts under test-output/pki/reports/. Skipped with the reason when OpenSSL is absent; a failure under PKINATIVE_INTEROP_REQUIRED=1 or the gate's --require-all.

A coverage canary holds the corpus to declared.conformant / declared.refused in docs/data/interop.json, so a silent regression cannot shrink the validated set. Per file the validator reports PASS / FAIL / XFAIL / XPASS / INFRA / SKIP; exit codes: 0 every expectation met, 1 a FAIL / XPASS / canary, 2 the corpus or dist/ missing, 3 OpenSSL required but absent. The vitest form of the same level-1 checks is tests/interop/openssl.test.ts (npm run test:interop), and tests/interop/lint.test.ts (npm run test:lint-certs, publish profile) runs the zlint and pkilint certificate linters over the corpus with the reviewed waivers of scripts/data/lint-waivers.json (none today).

The gate is blocking: the ci workflow runs it with --require-all on Linux (Node 22 and 24), Windows and macOS, and the interop workflow repeats it on four OS legs (ubuntu-22.04, ubuntu-24.04, windows-latest, macos-latest), two of which — interop (ubuntu-24.04) and interop (windows-latest) — are required status checks. OpenSSL is a runner tool, never a dependency. A PASS is validation evidence against a specific OpenSSL revision (3.5.5 on the development host), not a certification. See docs/guides/CONFORMANCE.md.

Autonomy proof

tests/autonomy.test.ts replays one scripted agent scenario (S0–S18: the handshake → the catalogue → describe_engine → inspect_certificate and the cache hit over the wire → the chain verdicts with CRL and OCSP evidence → name and purpose → a CA, a CSR and an issued leaf in file mode → a CMS signature signed, verified and then tampered → a time-stamp request built and a response verified → a PKCS#12 opened without a key byte in the transcript → resources/* → hostile inputs refused with a code and a remedy → the ceilings → protocol errors → draft_governance_issue → prompts/get → explain_code → a clean shutdown) against the built dist/cli.js on four transport × era pairs — stdio legacy, stdio modern, HTTP legacy, HTTP modern with PKINATIVE_MCP_HTTP_TOKEN — under a sandbox holding the fixtures, a cache directory and a lowered PKINATIVE_MCP_MAX_PATHS_EXPLORED ceiling (every instant pinned per call — the scenario asserts pinnedInstant: null), asserting no interaction, no unexpected isError, a code and a remedy on every refusal, a cache hit over the wire, no secret needle anywhere (stdout, stderr, the cache, the sandbox), a JSON-only stdout and a clean exit. To replay it by hand from Claude Code, Claude Desktop or the MCP Inspector, see docs/guides/LOCAL_TESTING.md (the repository ships a ready .mcp.json).

---

🧪 Local development

git clone https://github.com/Nizoka/pkinative-mcp.git
cd pkinative-mcp
npm ci --ignore-scripts   # .npmrc sets ignore-scripts=true: nothing builds on install
npm run gate:fast         # before every commit: typecheck:all, lint, test, code-tables, server-json, verify:docs
npm run gate              # the CI profile: + build, dist checks, stdio smoke test, tool shape, samples, coverage, docs, the OpenSSL corpus and interop
npx tsx scripts/gate.ts --publish --require-all   # release branches: everything incl. lint:certs (zlint / pkilint); a skipped step fails

npm run gate (scripts/gate.ts) is the single definition of green — 2381 tests across 111 files, the coverage thresholds of vitest.config.ts (94 / 90 / 95 / 94), and the built server driven over stdio, where stdout must carry JSON-RPC frames only and dist/ must hold no byte of a test key. It prints one line per step and writes the logs to test-output/.gate/<step>.log; --only <step> runs one step, --from <step> resumes, --json gives machine output (call the script directly to pass flags: PowerShell swallows a bare -- after npm run). The individual steps are ordinary npm scripts:

Script	What it does
npm run typecheck:all	tsc --noEmit over src/ + tests/, then scripts/
npm run lint	eslint src --max-warnings 0 — a warning fails
npm test / npm run test:coverage	vitest (dot reporter) / with v8 coverage — thresholds in vitest.config.ts
npm run build	tsc -p tsconfig.build.json → dist/
npm run examples:check	runs the 89 examples/*.json live through the tools/call handler (multi-step examples chained)
npm run test:generate / npm run verify:samples	the 98-sample baseline: the built server under the hermetic env → test-output/samples/, held to tests/_fixtures/samples.sha256.json (10 byte-exact, 3 by their TBS structure, 85 semantic)
npm run corpus:pki / npm run validate:pki	the OpenSSL corpus (23 + 5) written to test-output/pki/ and validated at levels 0 and 1
npm run test:interop / npm run test:lint-certs	the vitest form of level 1 (PKINATIVE_INTEROP_REQUIRED=1 fails instead of skipping) / the zlint + pkilint linters
npm run verify:tool-shape	the built tools/list structure against tests/_fixtures/tool-shape.json, under the 448 KiB catalogue and 8 KiB instructions budgets (npx tsx scripts/tool-shape.ts --write after a deliberate schema change only)
npm run verify:docs	every count, version, tool, code, operator variable, link and anchor in the docs held to docs/assets/ecosystem.json and the source tree
npm run agents:rules	regenerates .claude/rules/*.md from .github/instructions/*.instructions.md
npm run release:prepare	the mechanical version bump (never commits, tags or publishes)
npm run hooks:install / hooks:uninstall	opt-in git hooks (pre-commit: lint + a CRLF guard; pre-push: the fast gate)

Every script, its flags and its exit codes are listed in scripts/README.md. The 42 fixtures under tests/fixtures/pki/ were made by OpenSSL 3.5.5 (tests/fixtures/PROVENANCE.md), are pinned by SHA256SUMS, and are never regenerated in place: every private key there is public TEST-ONLY material (password test-only-password).

OpenSSL on your machine. Level 1 needs openssl 3.x on PATH (or OPENSSL_BIN). Linux: the distribution package. macOS: brew install openssl@3 (the system /usr/bin/openssl is LibreSSL and is refused with the reason). Windows: an OpenSSL 3 build on PATH, or the one that ships with Git for Windows (usr/bin/openssl.exe); point OPENSSL_BIN at it when it is not first on PATH. Without it, validate:pki and interop SKIP with the reason — and fail under --require-all.

Smoke-test the server over stdio:

node dist/cli.js
# In another terminal, send a JSON-RPC initialize request via stdin (e.g. with the MCP Inspector).
npx @modelcontextprotocol/inspector --cli node dist/cli.js --method tools/list

Run it over HTTP with a bearer token and a sandbox:

PKINATIVE_MCP_PORT=3000 PKINATIVE_MCP_HTTP_TOKEN=change-me-to-a-real-secret PKINATIVE_MCP_OUTPUT_DIR=/tmp/pki npx pkinative-mcp
# POST http://127.0.0.1:3000/mcp with Authorization: Bearer …

Contributors: start at AGENTS.md (the repository rules shared by every coding agent and contributor) and see docs/guides/LOCAL_TESTING.md for the full local-verification workflow — the quality gate, examples-as-tests, the sample baseline, the OpenSSL corpus, and driving the built server from Claude Code or the MCP Inspector.

📣 Release process

pkinative-mcp follows the same release formalism as pkinative, pdfnative-mcp and zipnative-mcp:

• One release note file per tag in release-notes/vX.Y.Z.md
• CHANGELOG.md mirrors each release bullet list
• GitHub Release body is copied from release-notes/vX.Y.Z.md
• npx tsx scripts/release-prepare.ts --version X.Y.Z applies the mechanical part of a version bump (it never commits, tags or publishes); the version moves in lock-step across package.json, src/version.ts, server.json and CITATION.cff (tests/metadata.test.ts) and in docs/assets/ecosystem.json (npm run verify:docs, rule manifest-shape)
• A release branch must pass npx tsx scripts/gate.ts --publish --require-all — every step, OpenSSL included, with no skip (the certificate linters run when zlint and pkilint are installed)
• npm publication is handled by GitHub Actions Trusted Publishing (OIDC), without NPM_TOKEN, from the protected npm-publish environment: the workflow checks that the tag equals the package version, runs the publish gate and publishes with --provenance; a second job attests the tarball (build provenance) together with a CycloneDX SBOM and attaches both to the GitHub Release
• Every Linux and Windows job starts with step-security/harden-runner (the action does not support macOS; the macOS job is the one documented exemption), checks out with persist-credentials: false, installs with npm ci --ignore-scripts and runs under least-privilege permissions; actions are pinned by commit SHA; the OpenSSL interoperability gate is blocking
• Human-in-the-loop: coding agents prepare and verify; the maintainer pushes, opens the pull request, tags and publishes (.github/AGENT_RULES.md)

See release-notes/TEMPLATE.md for the canonical structure and publication checklist, and CONTRIBUTING.md for the release procedure.

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📚 Project structure

src/
├── cli.ts                      # entrypoint: stdio (default, 256 MiB frames) or Streamable HTTP (PKINATIVE_MCP_PORT); reads the operator knobs once
├── http.ts                     # Node http <-> Web Request/Response bridge, 256 MiB body cap, Host/Origin loopback guard
├── auth.ts                     # opt-in HTTP bearer token (PKINATIVE_MCP_HTTP_TOKEN)
├── server.ts                   # Server factory, dispatch by tool kind, cache hints, the cache gate, SERVER_INSTRUCTIONS, 7 prompts, resources
├── caps.ts                     # every byte / count cap + the three operator ceilings
├── limits.ts                   # the 22 PkiLimits as the `limits` fragment; LIMIT_CEILING_EXCEEDED
├── sandbox.ts                  # the single filesystem boundary (PKINATIVE_MCP_OUTPUT_DIR): extension allow-lists, realpath checks, wx writes
├── pki-input.ts                # pem XOR derBase64 XOR path; PEM sniffing, label discipline, bundles
├── content-input.ts            # text XOR base64 XOR path for the bytes to sign / verify / time-stamp; the HEX grammar
├── parse-context.ts            # the PARSE fragment (encodingRules, pemMode, strict, limits) and the per-call input budget
├── signer.ts                   # PKCS#8 / PKCS#12 -> non-extractable SigningKey; the algorithm rules (rsaScheme, hashes)
├── secrets.ts                  # the two password channels (input XOR PKINATIVE_MCP_PASSWORD), redaction
├── key-views.ts                # allow-list views of keys and PKCS#12 bags (never a key byte)
├── trust.ts                    # the TRUST fragment (anchors, candidates, evidence, at, purposes, policy) and reasons[]
├── time.ts                     # ISO 8601 instants, PKINATIVE_MCP_AT, clock-dependence
├── random.ts                   # serialNumber:'random' / nonce:'random' (node:crypto), reported in summaries
├── x509-spec.ts, asn1-spec.ts  # the closed JSON specs of create_certificate / create_csr / encode_* (depth-bounded, pollution-safe)
├── names.ts, spki.ts           # host / IP identity inputs; public-key kinds and curves
├── pki-errors.ts               # PkiError -> ToolError (the 57 PKI_* codes verbatim, classes, remedies), guard()
├── wrapper-codes.ts            # the 21 wrapper codes with meaning and remedy (served by explain_code)
├── diagnostics.ts              # engine diagnostic sink (de-duplicated, capped at 200) -> diagnostics[]; strict escalation
├── projection.ts               # verbosity / fields projection for the read and verdict tools
├── output.ts                   # artefact emitter: embedded resource (pem / der / hex) or exclusive sandbox file
├── resources.ts                # pkinative://output/{+path} over the sandbox (key-bearing files never listed nor served)
├── cache.ts                    # opt-in SHA-256 response cache (PKINATIVE_MCP_CACHE_DIR)
├── views.ts, wire.ts, base64.ts  # wire views (no raw DER echoes), hex helpers, base64 boundary diagnostics
├── engine.ts                   # engine version and Node floor, the Web Crypto capability probe
├── governance.ts               # AI-governance / HITL contract text + draft validation
├── errors.ts, version.ts, index.ts
├── data/pkinative/             # the registries vendored at the pkinative v1.0.0 tag: errors, reasons, diagnostics, limits, core-exports + generated code-tables.ts
└── tools/                      # one file per tool (34), _definition.ts (kinds, annotations), _registry.ts + _group-*.ts (catalogue order), _shared.ts
scripts/                        # TypeScript run by tsx — the full table is in scripts/README.md
├── gate.ts                     # THE quality gate (npm run gate / gate:fast; --publish --require-all on release branches)
├── generate-samples.ts         # npm run test:generate — the examples through the built server -> test-output/samples/
├── verify-samples.ts           # npm run verify:samples — the 98-sample baseline (tests/_fixtures/samples.sha256.json)
├── generate-pki-corpus.ts      # npm run corpus:pki — the OpenSSL interoperability corpus (23 + 5)
├── validate-pki.ts             # npm run validate:pki — level 0 (engine round trip) + level 1 (OpenSSL 3.x); exit 0 / 1 / 2 / 3
├── tool-shape.ts               # structural tools/list fingerprint and size budgets (--write refreshes the fixture)
├── verify-docs.ts              # npm run verify:docs — the docs held to docs/assets/ecosystem.json and the source tree
├── release-prepare.ts          # mechanical version bump (never commits, tags or publishes)
├── build-claude-rules.ts       # npm run agents:rules — .github/instructions/ -> .claude/rules/
├── build-code-tables.mjs       # regenerates src/data/pkinative/code-tables.ts from the vendored registries
├── verify-issue.mjs            # governance draft checker (npm run verify:issue)
├── lib/                        # pki-corpus, interop-tools (OpenSSL), sample-fingerprint, tool-shape, mcp-surface, markdown-anchors, agent-config, prose-language, json-schema-lite
└── helpers/, data/, validators/  # hermetic env, I/O, the lint waivers, the pkilint driver
docs/
├── AGENT_CONTRACT.md           # the consumer contract for agents that USE the server (catalogue, decision tree, recipes, error reference)
├── AI_GUIDE.md, KNOWLEDGE_BASE.md, API_STABILITY.md
├── guides/                     # AI_GOVERNANCE, LOCAL_TESTING, SECURITY, SIGNING, VERIFICATION, REVOCATION, TIMESTAMPS, KEYS, CONFORMANCE, REPRODUCIBLE
├── data/                       # errors, reasons, diagnostics, limits, core-exports (mirrors of src/data/pkinative/), interop.json (the corpus counts)
└── assets/ecosystem.json       # the single source of every count and version quoted in the docs
examples/                       # 89 executable tools/call sequences (npm run examples:check)
AGENTS.md, CLAUDE.md            # repository rules for coding agents; .github/instructions/ holds the per-area rules
.claude/                        # shared agent settings, the fail-closed guard hook, generated rules, the release-audit skill
.github/workflows/              # ci (Linux Node 22 / 24, Windows, macOS — the gate with --require-all), interop (4 OS legs, blocking),
                                #   sample-regression, publish (Trusted Publishing + SBOM + attestation), docs, codeql, scorecard,
                                #   dependency-review, audit, node-current
.github/rulesets/               # branch and tag rulesets to import
tests/                          # vitest suites (one per tool / module), _fixtures/ (tool shape, sample baseline, the registry schema),
                                #   fixtures/pki/ (42 OpenSSL-made TEST-ONLY files, SHA256SUMS, PROVENANCE.md), interop/ (OpenSSL, linters), tools/ (repository tooling)

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🗺 Roadmap

v1.0.0 is the first release, on pkinative 1.0.0: the whole runtime surface of the engine (117 / 117 runtime exports reached by a named tool), offline. The full plan — the released milestone, what is blocked upstream, next steps and the long-term direction — lives in ROADMAP.md.

Blocked upstream, by design (the engine does not have it, and a thin wrapper will not fake it):

• Key generation — pkinative generates nothing; keys come from your HSM, KMS or openssl genpkey.
• Writers for PKCS#8, PKCS#12, CRL, OCSP response and time-stamp response — the engine has none; issue them with your CA software or OpenSSL and verify them here.
• DSA and ML-DSA verification — parsed, reported, never verified or signed (PKI_REASON_SIGNATURE_NOT_CHECKED / UNSUPPORTED_KEY).

Have a feature idea? Open an issue or PR — or let an agent draft one with draft_governance_issue and submit it yourself.

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⭐ Star the project

If pkinative-mcp is useful to you, please ⭐ this repository — and consider also starring the underlying engine Nizoka/pkinative. Stars help others discover the project and motivate continued development.

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🤝 Contributing

Contributions are very welcome. Please read CONTRIBUTING.md, check the open issues, and follow the code of conduct.

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📄 License

MIT © 2026 Nizoka. Third-party material: THIRD-PARTY-NOTICES.md.

pkinative-mcp is built on top of pkinative and the Model Context Protocol TypeScript SDK.