Pdfnative MCP Server

pdfnative-mcp

Model Context Protocol (MCP) server that bridges the pdfnative library — a zero-dependency, ISO 32000-1 compliant PDF engine — to any MCP-compatible AI client (Claude Desktop, Cursor, Continue, ChatGPT, Zed, …).

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✨ Features

pdfnative-mcp exposes 24 production-grade tools to any MCP host:

New in v1.5.0:

• 📊 Native vector charts — add_chart renders bar / horizontal-bar / line / pie / donut charts as pure PDF path operators (zero rasterisation, PDF/A-safe with auto alt text). generate_basic_pdf also accepts a chart block for composition with text and tables.
• 📝 Fill & flatten forms — read_form_fields lists an existing AcroForm's fields; fill_form fills and/or flattens it via a non-destructive incremental update (the counterpart to add_form).
• 🔐 Encryption round-trip — encrypt_pdf re-secures with AES-128 / AES-256 (RC4 never emitted), decrypt_pdf recovers an unencrypted copy, a password input opens encrypted sources on the read-only tools, and merge_pdfs / split_pdf / extract_pages gain password + encrypt.
• 🔤 Real text extraction — extract_text now resolves each font's /ToUnicode CMap (no more glyph-index output) and can return positioned runs.
• 🔗 Native MCP resources — sandboxed generated PDFs become pdfnative://output/… resources (resources/list + resources/read), with a resource_link in file-mode results for cross-call re-reference.
• 🏷️ Tool annotations — every tool advertises readOnlyHint / destructiveHint / idempotentHint / openWorldHint.
• ⬆ Engine upgrade — pdfnative v1.6.0 (decrypt/re-encrypt, extractText, fill/flatten, charts; colour-emoji subset 221 → 1167 glyphs).

New in v1.4.0:

• 🤝 AI governance + human-in-the-loop — draft_governance_issue lets an agent draft a fully compliant GitHub issue locally (draft .md + machine-readable compliance report). The agent is a draftsman, never an autonomous submitter: a human is the only gate, and the server makes zero GitHub writes and no outbound network calls. Backed by the governance_contract and draft_issue_workflow MCP prompts.
• ✏️ Markup annotations — annotate_pdf overlays highlight, sticky-note, underline, strikeout, squiggly, square, circle, line, and freetext annotations on an existing PDF via incremental update. It is a visual review layer, not a redaction — underlying bytes remain.
• 🔢 Page labels in inspect_pdf — read-only surfacing of /PageLabels ranges (roman, decimal, prefixed).
• ∑ Math / scientific script — add_international_text accepts lang: 'math' (explicit, like emoji) to embed the Noto Sans Math face on demand.
• 🧩 MCP prompts — the server now advertises the prompts capability with governance_contract and draft_issue_workflow.
• ⬆ Engine upgrade — pdfnative v1.5.0.

New in v1.3.0:

• 🆕 Three page-tree tools — merge_pdfs, split_pdf, extract_pages (built on pdfnative v1.4.0's page-tree API; encrypted sources are rejected).

• 🔖 Bookmarks, page labels & nested lists — generate_basic_pdf gains outline ('auto' or explicit tree), pageLabels, multi-level list items, and viewerPreferences.

• 📐 Table cell borders & alignment — add_table gains cellBorders, cellVAlign, and viewerPreferences; add_international_text gains viewerPreferences.

• 🔐 Constant-time signing — sign_pdf signs RSA and EC-DER keys through a node:crypto provider with a transparent pure-JS fallback; signatures stay interoperable.

• ⬆ Engine upgrade — pdfnative v1.4.0.

• 🆕 Tool extract_attachments — read embedded files back out of a PDF (completes the Factur-X / ZUGFeRD round-trip) with byte-for-byte payloads, a filename filter, and an includeData: false metadata-only probe.

• 💧 Watermarks — generate_basic_pdf and add_table accept an optional watermark (text, opacity, angle, colour, position) rendered on every page.

• 🌐 Unicode normalize — opt-in NFC/NFD/NFKC/NFKD on generate_basic_pdf and add_international_text.

• 🪙 Token-frugal reads — the read-only tools (inspect_pdf, verify_pdf, validate_pdf, extract_text, extract_attachments) accept optional verbosity: 'summary' and fields: […] inputs for ~90% smaller responses on large results, with no loss of the fields agents branch on. Defaults are unchanged.

• 🪙 No base64 duplication — generated PDFs (base64 mode) are returned once as an embedded resource content block instead of also being copied into structuredContent.

• 🔧 MCP registry publish fix — mcpName now uses the canonical GitHub login casing (io.github.Nizoka/pdfnative-mcp) so the registry's case-sensitive validation accepts the npm package.

• ⬆ Dependency — upgraded to zod 4.

New in v1.1.0:

• 🆕 Tool validate_pdf — read-only PDF/UA (ISO 14289-1) structural conformance check.
• 🆕 Six new scripts — Telugu, Sinhala, Tibetan, Khmer, Myanmar, Ethiopic (24 scripts total).
• 🆕 COLRv1 colour emoji — native colour emoji with monochrome fallback.
• 🆕 Newline sanitizer — embedded \n in paragraphs auto-splits into separate paragraphs (Safe PDF/A).
• 🆕 Automatic NFC normalisation for add_international_text.
• 🛠 Engine upgrade — pdfnative v1.3.0: the Euro sign / CP-1252 symbols now extract correctly, and wrapped table cells get unique per-line MCIDs (PDF/UA-safe).

New in v1.0.0:

• 🆕 Three new tools: verify_pdf, add_attachment (Factur-X / ZUGFeRD), extract_text.
• 🆕 Smart-table fields: wrap, repeatHeader, zebra, caption, minRowHeight, cellPadding.
• 🆕 inspect_pdf now reports hasSignaturePlaceholder and per-attachment summary; new check values 'placeholder' and 'attachments'.
• 🆕 Signing ergonomics: sign_pdf accepts ECDSA SEC1 / PKCS#8 DER keys and auto-injects a /Sig placeholder when missing (one-call signing of any PDF).
• 🆕 Opt-in cache (PDFNATIVE_MCP_CACHE_DIR): SHA-256 keyed, 1 h TTL, 256 MiB LRU.
• 🆕 _meta.apiVersion and per-tool _meta.examples for AI-agent discovery — see docs/API_STABILITY.md.
• 🆕 AI agent guide: docs/AI_GUIDE.md — decision tree + common pitfalls. See also the root AGENTS.md operations manual.
• 🆕 PDF/A authoring guide: docs/guides/PDFA.md.
• 🛠 Env-var rename: PDFNATIVE_MCP_OUTPUT_DIR (was PDFNATIVE_MPC_OUTPUT_DIR; old name still works with a one-shot deprecation warning).
• ✅ Now shipped: merge_pdfs, split_pdf, extract_pages (v1.3.0), annotate_pdf (v1.4.0), and the add_chart / read_form_fields / fill_form / encrypt_pdf / decrypt_pdf tools plus the encrypted round-trip and native MCP resources (v1.5.0). redact_pdf stays deferred — pdfnative can overlay/flatten but not remove page content, and an overlay-only "redaction" would create false security, so it is intentionally not shipped (tracked as an upstream content-removal request).

All tools support two output modes:

• base64 (default) — the generated PDF is returned once as an embedded resource content block (a data:application/pdf;base64,… URI); structuredContent carries only { mode, sizeBytes }.
• file — the PDF is written to a sandboxed directory configured via PDFNATIVE_MCP_OUTPUT_DIR. File output is disabled unless this variable is set; absolute paths, path traversal, non-.pdf extensions, and NUL bytes are all rejected.

Upgrading from v1.1.0: the only behaviour change is that base64-mode bytes are no longer duplicated into structuredContent.base64. Read them from the embedded resource block instead:

- const base64 = response.structuredContent.base64;   // v1.1.0
+ const block = response.content.find((c) => c.type === 'resource');
+ const base64 = block.resource.blob;                  // v1.2.0

Token-frugal reads (v1.2.0). The four read-only tools accept two optional inputs:

• verbosity: 'summary' — returns a compact scalar-only verdict (drops the heavy arrays / full text). E.g. verify_pdf → { signatureCount, allValid, invalid, summary }.
• fields: ['a', 'b.c'] — projects the structured result to named dot-paths; composes after verbosity. Unknown paths are omitted leniently.

Smallest “is this PDF signed and valid?” probe: { "pdfBase64": "…", "verbosity": "summary", "fields": ["allValid"] }.

Why pdfnative?

pdfnative-mcp inherits every guarantee of the underlying engine:

• Zero runtime dependencies — pure JavaScript, no native bindings.
• ISO 32000-1 (PDF 1.7) compliant output.
• PDF/A-1b/2b/3b, AES-128/256 encryption, AcroForm, digital signatures.
• 16 Unicode scripts with built-in BiDi reordering, Arabic positional shaping, Thai/Devanagari/Bengali/Tamil OpenType shaping.
• Tree-shakeable ESM build.

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🚀 Installation

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

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

Requirements: Node.js ≥ 22.

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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": {
    "pdfnative": {
      "command": "npx",
      "args": ["-y", "pdfnative-mcp"],
      "env": {
        "PDFNATIVE_MCP_OUTPUT_DIR": "/Users/you/Documents/mcp-pdfs"
      }
    }
  }
}

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": {
    "pdfnative": {
      "command": "npx",
      "args": ["-y", "pdfnative-mcp"],
      "env": { "PDFNATIVE_MCP_OUTPUT_DIR": "/Users/you/Documents/mcp-pdfs" }
    }
  }
}

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

🌐 Supported AI Ecosystem & Clients

pdfnative-mcp is designed for MCP-native environments and works with clients that support MCP over stdio.

Community-verified compatibility includes:

• Ontheia — a self-hosted, open-source AI agent platform (privacy-first). Reported as working out of the box in issue #41 and listed on Ontheia's compatible MCP servers page.

Environment variables

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🛠 Tool reference

generate_basic_pdf

{
  "title": "Q1 2026 Report",
  "blocks": [
    { "type": "heading", "text": "Executive summary", "level": 1 },
    { "type": "paragraph", "text": "Revenue grew 24% year over year." },
    { "type": "list", "style": "bullet", "items": ["Strong APAC", "Stable EU", "Soft NA"] },
    { "type": "pageBreak" },
    { "type": "heading", "text": "Details", "level": 2 }
  ],
  "footerText": "Confidential — Internal use only",
  "outputMode": "base64"
}

add_barcode

{
  "format": "qr",
  "data": "https://pdfnative.dev",
  "caption": "Scan to learn more",
  "ecLevel": "H",
  "outputMode": "file",
  "outputPath": "tickets/event-42.pdf"
}

Supported formats: qr, code128, ean13, datamatrix, pdf417.

add_international_text

{
  "title": "مرحبا بالعالم",
  "lang": "ar",
  "paragraphs": [
    "هذا اختبار للنص العربي مع تشكيل OpenType ومحارف ثنائية الاتجاه.",
    "Mixed content: العربية + English ✓"
  ]
}

Supported lang codes: ar, he, th, ja, zh, ko, el, hi, bn, ta, ru, ka, hy, tr, vi, pl, latin, emoji, math.

Multi-script documents — pass an array or comma-separated list:

{
  "title": "Mixed Script",
  "lang": ["ar", "emoji"],
  "paragraphs": ["العربية مع رموز 🎉🚀"],
  "pdfA": "pdfa2u"
}

sign_pdf

As of v1.0.0, sign_pdf auto-injects a /Sig placeholder when missing — you can sign any PDF in one call:

{
  "pdfBase64": "<any base64 PDF>",
  "algorithm": "rsa-sha256",
  "certDerBase64": "<base64 X.509 cert in DER>",
  "rsaKeyPkcs1DerBase64": "<base64 PKCS#1 RSAPrivateKey DER>",
  "signerName": "Alice",
  "reason": "Approval",
  "location": "Paris, FR",
  "signingTime": "2026-01-15T10:30:00Z"
}

For ECDSA P-256: use algorithm: "ecdsa-sha256" and supply either ecPrivateKeyDerBase64 (SEC1 or PKCS#8 DER) or ecPrivateScalarHex (64 hex chars).

PEM → DER conversion:

openssl x509 -in cert.pem -outform DER | base64 -w0                 # cert
openssl rsa  -in key.pem  -outform DER -traditional | base64 -w0    # RSA PKCS#1
openssl pkey -in key.pem  -outform DER | base64 -w0                 # ECDSA

Use prepare_signature_placeholder only when you need to customize the placeholder (e.g. larger placeholderBytes for >4096-bit RSA keys). Otherwise call sign_pdf directly.

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add_table

{
  "title": "Monthly Sales",
  "headers": ["Region", "Units", "Revenue"],
  "rows": [
    ["APAC", "1200", "$240,000"],
    ["EMEA", "800", "$160,000"]
  ],
  "infoItems": [{ "label": "Period", "value": "January 2025" }],
  "footerText": "Internal use only",
  "outputMode": "base64"
}

add_form

{
  "title": "Employee Onboarding",
  "fields": [
    { "fieldType": "text", "name": "fullName", "label": "Full Name", "required": true },
    { "fieldType": "dropdown", "name": "dept", "label": "Department", "options": ["Engineering", "Sales", "HR"] },
    { "fieldType": "checkbox", "name": "agree", "label": "I agree to the terms", "checked": false }
  ],
  "outputMode": "base64"
}

embed_image

{
  "title": "Product Photo",
  "imageBase64": "<base64-encoded JPEG bytes>",
  "mimeType": "image/jpeg",
  "caption": "Front view of Model X",
  "width": 400,
  "outputMode": "base64"
}

Note: pdfnative does not support alpha-channel PNGs (color type 6). Pre-process such images to remove the alpha channel before embedding.

prepare_signature_placeholder

{
  "title": "Service Agreement",
  "signerName": "Alice Dupont",
  "reason": "Approved",
  "location": "Paris, FR",
  "blocks": [
    { "type": "paragraph", "text": "By signing below, I accept the terms and conditions." }
  ],
  "outputMode": "base64"
}

Pass the returned PDF bytes to sign_pdf to complete the signing workflow.

inspect_pdf

Read-only structural and security inspection — useful for downstream verification, CI assertions, and AI agents that need to reason about a PDF before acting on it.

{
  "pdfBase64": "<base64 PDF>",
  "pages": true,
  "check": ["pdfa", "signed", "attachments"]
}

Returns:

{
  "version": "1.7",
  "pageCount": 3,
  "encryption": "none",          // 'none' | 'aes-128' | 'aes-256' | 'rc4' | 'unknown'
  "pdfA": "3B",                  // null when no PDF/A claim is present
  "signatureCount": 1,
  "hasSignaturePlaceholder": false,
  "attachments": [{ "filename": "factur-x.xml", "mimeType": "application/xml", "sizeBytes": 1234, "relationship": "Source" }],
  "info": { "Producer": "pdfnative", "Title": "Invoice INV-2025-001" },
  "perPage": [{ "index": 0, "width": 595, "height": 842 }],
  "checks": { "pdfa": true, "signed": true, "attachments": true },
  "checksPassed": true
}

check[] accepts any of 'pdfa', 'signed', 'encrypted', 'placeholder', 'attachments'. checksPassed is the AND of all requested checks.

validate_pdf

Read-only PDF/UA (ISO 14289-1) structural conformance check for a Tagged PDF. Generate an accessible document with any tool using pdfA (e.g. pdfA: 'pdfa2u'), then validate the result:

{ "pdfBase64": "<tagged-pdf-base64>" }

Returns:

{
  "standard": "pdf-ua-1",
  "valid": true,
  "errors": [],          // blocking structural violations (empty when valid)
  "warnings": [],        // non-blocking best-practice recommendations
  "summary": "PDF/UA structural prerequisites hold."
}

It verifies catalog /MarkInfo /Marked true, /StructTreeRoot (+ /ParentTree), /Metadata (XMP), /Lang, and per-page MCID uniqueness. This is a fast developer-time gate — not a substitute for a full reference validator (veraPDF), which additionally checks fonts, colour, and rendering.

annotate_pdf

Overlay markup annotations on an existing PDF via incremental update. This is a visual review layer, not a redaction — the underlying content is untouched.

{
  "pdfBase64": "<base64 PDF>",
  "annotations": [
    { "type": "highlight", "page": 0, "rect": [72, 700, 520, 715], "color": [1, 1, 0], "contents": "Check this figure" },
    { "type": "text", "page": 0, "rect": [540, 700, 560, 720], "contents": "Reviewer note" }
  ]
}

Types: text, highlight, underline, strikeout, squiggly, square, circle, line, freetext. Encrypted sources are rejected (ENCRYPTED_SOURCE).

draft_governance_issue

Draft a governance-compliant GitHub issue locally for a human to review and submit. The server never contacts GitHub and makes no outbound network calls; it returns the draft Markdown plus a machine-readable compliance report.

{
  "title": "add_table drops the caption on the second page",
  "issueType": "bug",
  "summary": "The table caption is only rendered on page 1 when repeatHeader is true.",
  "reproduction": { "command": "node examples/run.mjs add-table-caption.json", "result": "Page 2 has no caption row." },
  "expectedBehavior": "The caption repeats with the header on every page.",
  "duplicateSearchPerformed": true
}

A draft that proposes a runtime dependency, omits a reproduction, or sets duplicateSearchPerformed: false is rejected with GOVERNANCE_VIOLATION. See docs/guides/AI_GOVERNANCE.md for the full human-in-the-loop contract.

verify_pdf, add_attachment, extract_text

See the dedicated sections in docs/AI_GUIDE.md and the reference in docs/KNOWLEDGE_BASE.md. Ready-to-run examples live under examples/.

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🔐 Security model

pdfnative-mcp runs inside the host process and exposes a stdio MCP server. It does not open network sockets and does not perform any I/O outside the configured sandbox.

• File writes are gated by PDFNATIVE_MCP_OUTPUT_DIR. When unset, the file output mode is rejected with a SecurityError.
• Path resolution rejects absolute paths, traversal sequences (..), NUL bytes, and any extension other than .pdf.
• Output size is capped at 50 MB per call.
• Inputs are validated against strict JSON Schemas + Zod runtime checks at the boundary of every tool.

See SECURITY.md for the responsible disclosure process.

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🧪 Local development

git clone https://github.com/Nizoka/pdfnative-mcp.git
cd pdfnative-mcp
npm install
npm run typecheck
npm run lint
npm test
npm run build

Smoke-test the server over stdio:

node dist/cli.js
# In another terminal, send a JSON-RPC initialize request via stdin (e.g. with mcp-inspector).

Contributors: see docs/guides/LOCAL_TESTING.md for the full local-verification workflow — the quality gate, examples-as-tests, validating that generated PDFs are structurally correct (assertValidPdf, inspect_pdf, validate_pdf, verify_pdf), opening output in a viewer, external PDF/A checking with veraPDF, and the MCP Inspector.

📣 Release process

pdfnative-mcp follows the same release formalism as pdfnative:

• 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
• npm publication is handled by GitHub Actions Trusted Publishing (OIDC), without NPM_TOKEN

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

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📚 Project structure

src/
├── cli.ts                      # stdio entrypoint (#!/usr/bin/env node)
├── index.ts                    # public library exports
├── server.ts                   # McpServer factory + tool registry
├── output.ts                   # sandboxed file writer / base64 emitter (single + multi)
├── text.ts                     # newline sanitizer (Safe PDF/A)
├── doc-features.ts             # nested lists, outline, page labels, viewer prefs
├── pagetree.ts                 # page-tree error mapping (merge/split/extract)
├── crypto-provider.ts          # node:crypto constant-time signature provider
├── errors.ts                   # ToolError, SecurityError
└── tools/
    ├── generate-basic-pdf.ts
    ├── add-barcode.ts
    ├── sign-pdf.ts
    ├── add-international-text.ts
    ├── add-table.ts
    ├── add-form.ts
    ├── embed-image.ts
    ├── inspect-pdf.ts
    ├── verify-pdf.ts
    ├── validate-pdf.ts
    ├── add-attachment.ts
    ├── extract-attachments.ts
    ├── extract-text.ts
    ├── merge-pdfs.ts
    ├── split-pdf.ts
    ├── extract-pages.ts
    └── prepare-signature-placeholder.ts
tests/                          # vitest suites

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🗺 Roadmap

v1.3.0 is shipped. The full plan — released milestones, in-progress work, and long-term direction — lives in ROADMAP.md.

Blocked upstream (page-tree manipulation):

• redact_pdf and an encrypted-PDF round-trip — pdfnative does not yet export the content-redaction / decryption primitives required to build these safely. They remain on the roadmap, blocked on an upstream API. (merge_pdfs, split_pdf and extract_pages shipped in v1.3.0.)

Have a feature idea? Open an issue or PR.

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⭐ Star the project

If pdfnative-mcp is useful to you, please ⭐ this repository — and consider also starring the underlying engine Nizoka/pdfnative. 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

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