Bilig MCP Server

bilig

Formula workbooks for Node services and agent tools.

Use @bilig/workpaper when a calculation is easiest to review as cells and formulas, but it has to run in a Node service, queue worker, serverless route, test, or coding-agent tool. Use @bilig/xlsx-formula-recalc when the immediate problem is "I changed XLSX inputs in Node and need the formula results now," including SheetJS / xlsx pipelines that already produce XLSX bytes. Use @bilig/exceljs-formula-recalc when the workbook is already moving through ExcelJS.

@bilig/headless remains the full lower-level runtime package with bundled agent metadata. The unscoped packages remain published as compatibility and search aliases, but scoped @bilig/* packages are the canonical install path.

It gives you a WorkPaper: build sheets, write inputs, recalculate, read the cell value, and save the workbook as JSON. No browser grid is involved. The published package also carries AGENTS.md and SKILL.md so coding agents inspecting node_modules/@bilig/workpaper can find the write/read/persist loop locally. The public docs expose the same path through AGENTS.md, skill.md, docs/.well-known/agent.json, AI spreadsheet agent tool, and llms-full.txt.

Good fits: pricing rules, budget checks, payout models, import validation, and agent tools that need read-after-write proof. Bad fits: manual spreadsheet editing, Office macros, desktop Excel automation, or one-off arithmetic where a workbook would be ceremony.

Project site: https://proompteng.github.io/bilig/

Which Package Should I Install?

Stale XLSX Formula Values? Run This First

If a Node job already has an XLSX file and only needs fresh formula values before returning, use the file-level recalculation package before evaluating the broader WorkPaper runtime:

npx --package @bilig/sheetjs-formula-recalc sheetjs-recalc --demo --json

npx --package @bilig/xlsx-formula-recalc xlsx-recalc --demo --json

npx --package @bilig/xlsx-formula-recalc xlsx-recalc quote.xlsx \
  --set Inputs!B2=42 \
  --read Summary!B7 \
  --out quote.recalculated.xlsx \
  --json

If the workbook is already in ExcelJS, keep that boundary and add @bilig/exceljs-formula-recalc:

npm install exceljs @bilig/exceljs-formula-recalc
npx --package @bilig/exceljs-formula-recalc exceljs-recalc --demo --json

For one checkout proof across SheetJS/xlsx, xlsx-populate, and ExcelJS:

npm --prefix examples/recalc-bridge-workflows install
npm --prefix examples/recalc-bridge-workflows run smoke

Choose An Evaluation Path

Reduced workbook already in hand? Generate the paste-ready fixture report in one command:

npm exec --package @bilig/headless@0.40.21 -- bilig-formula-clinic ./reduced.xlsx --cells "Summary!B7,Inputs!B2"

Handing a spreadsheet task to another coding agent? Start with the agent handoff prompt before opening Excel, LibreOffice, Google Sheets, or a screenshot UI. To prove the package-owned agent loop without cloning the repo or downloading a TypeScript file:

npm exec --package @bilig/headless@0.40.21 -- bilig-agent-challenge
npm exec --package @bilig/headless@0.40.21 -- bilig-mcp-challenge

Agent tools that support skill manifests can start from skill.md or the well-known index at docs/.well-known/agent-skills/index.json. Claude Desktop users can also install the released MCPB bundle directly: https://github.com/proompteng/bilig/releases/download/libraries-v0.40.21/bilig-workpaper.mcpb. If you need a copy-paste eval for another tool host, use the agent workbook challenge: one input edit, one dependent formula readback, one serialized restore, and a verified: true proof object.

Try It In 90 Seconds

This uses the published npm package. It builds a workbook, changes one input, reads the calculated value, saves JSON, restores the workbook, and prints the same value again.

mkdir bilig-headless-eval
cd bilig-headless-eval
npm init -y
npm pkg set type=module
npm install @bilig/workpaper
npm install -D tsx typescript @types/node
curl -fsSLo quickstart.ts https://proompteng.github.io/bilig/npm-eval.ts
npx tsx quickstart.ts

Expected output:

{
  "before": 24000,
  "after": 38400,
  "afterRestore": 38400,
  "sheets": ["Inputs", "Summary"],
  "bytes": 999,
  "verified": true,
  "nextStep": "If this proof matches your service or agent workflow, star or bookmark Bilig: https://github.com/proompteng/bilig/stargazers"
}

The TypeScript file is maintained in examples/headless-workpaper/npm-eval.ts. The exact byte count can change between package versions; verified: true and matching after/afterRestore values are the check.

For a route-shaped quote approval API today, run the maintained example:

git clone --depth 1 https://github.com/proompteng/bilig.git
cd bilig
pnpm --dir examples/serverless-workpaper-api install --ignore-workspace
pnpm --dir examples/serverless-workpaper-api run smoke

For a generated project from a blank directory, run npm create @bilig/workpaper@latest pricing-workpaper through the @bilig/create-workpaper package. The package source lives in packages/create-workpaper, and the publish gate is documented in create a Bilig WorkPaper starter. For an agent-ready project with AGENTS.md, MCP client configs, and an agent:verify script, run npm create @bilig/workpaper@latest pricing-agent -- --agent.

If that proof matches a service or agent workflow you maintain, the useful next step is concrete feedback: star or bookmark the repo, then open or answer one adoption blocker in Discussions: formula coverage, stale XLSX cached values, persistence shape, MCP/agent writeback, or benchmark coverage.

TypeScript API Shape

Most integrations are just this: build a workbook, write an input, read the calculated value, and save the workbook state.

import { WorkPaper, exportWorkPaperDocument, serializeWorkPaperDocument } from '@bilig/workpaper'

const workbook = WorkPaper.buildFromSheets({
  Inputs: [
    ['Metric', 'Value'],
    ['Customers', 20],
    ['Average revenue', 1200],
  ],
  Summary: [
    ['Metric', 'Value'],
    ['Revenue', '=Inputs!B2*Inputs!B3'],
  ],
})

const inputs = workbook.getSheetId('Inputs')
const summary = workbook.getSheetId('Summary')
if (inputs === undefined || summary === undefined) {
  throw new Error('Workbook is missing required sheets')
}

workbook.setCellContents({ sheet: inputs, row: 1, col: 1 }, 32)

const revenue = workbook.getCellDisplayValue({ sheet: summary, row: 1, col: 1 })
const saved = serializeWorkPaperDocument(exportWorkPaperDocument(workbook, { includeConfig: true }))

console.log({ revenue, savedBytes: saved.length })

When To Reach For It

Use @bilig/workpaper when:

• a Node service owns a workbook-shaped calculation;
• an agent needs tools such as readRange and setInputCell, with computed before/after values instead of screenshots;
• tests need deterministic spreadsheet state and formula readback;
• a workflow needs to save the edited workbook as JSON and restore it later.

Use something else when you need a visual spreadsheet grid, Office macros, desktop Excel automation, or a one-off arithmetic helper. Do not treat embedded XLSX cached formula values as truth; use the Excel oracle workflow when accuracy matters.

Package Boundary

Current checked npm footprint for @bilig/headless@0.40.21:

• Pack dry run: 653 kB tarball, 3.99 MB unpacked, 657 package entries.
• Boundary: the main import is the WorkPaper formula/JSON runtime; XLSX import/export stays behind the @bilig/headless/xlsx subpath; MCP is the bilig-workpaper-mcp binary wrapper; reduced workbook reports use the bilig-formula-clinic binary.
• Cold-start gate: Node imports the main entrypoint, builds a two-sheet WorkPaper, and reads 24000 under 1000 ms without importing the XLSX subpath.
• Runtime: Node >=22.0.0; Node 22 compatibility is covered by the runtime package workflow.

Published Package Trust

@bilig/headless is published with npm registry signatures and SLSA provenance attestations. Verify the package version you are about to adopt:

npm view @bilig/headless@latest version dist.attestations dist.signatures --json

After installing, npm can verify the current dependency tree:

npm audit signatures

The current package trust path is documented in npm provenance and package trust. Repository security posture is tracked by OpenSSF Scorecard and uploaded to GitHub code scanning on every main update.

Start Here

Use the shortest path that proves the package against a real job.

1. Run the 90-second npm eval in a blank project.
2. Run the flagship serverless WorkPaper API example: npm run quote-approval-api.
3. If the workflow starts with an XLSX file, run the XLSX formula recalculation in Node: npm start.
4. If an agent needs workbook tools, start with the headless WorkPaper agent handbook, then use the MCP server guide when the caller is an MCP client.
5. If a real workbook almost works, start with the formula bug clinic. Then submit a reduced public fixture so the blocker can become a test, example, or corpus case instead of private feedback. Form: https://github.com/proompteng/bilig/issues/new?template=workbook_fixture.yml. Discussion: https://github.com/proompteng/bilig/discussions/414.

The rest of the docs are an index, not a prerequisite.

For comparison and integration details, use the plain-language fit guide, screenshot automation boundary, Google Sheets API boundary, workbook automation examples, the formula workbooks proof page, the Node spreadsheet formula engine guide, server-side spreadsheet automation, framework adapters, formula bug clinic, workbook fixture submissions, OpenAI Agents SDK tools, AI SDK and LangChain tools, CrewAI adapter, the headless WorkPaper agent handbook, the MCP server guide, spreadsheet MCP server comparison, MCP directory status, MCP client setup, Claude Desktop MCPB bundle, npm provenance and package trust, JavaScript library comparison, headless spreadsheet engine for Node services and agents, XLSX formula recalculation in Node.js, agent XLSX formula recalculation without LibreOffice, Excel file as a Node calculation engine, stale XLSX formula cache in Node.js, SheetJS formula result not updating in Node.js, Microsoft Graph Excel recalculation in Node.js, xlsx-calc alternative for Node workbook recalculation, ExcelJS formula recalculation in Node.js, ExcelJS shared formulas in Node.js, SheetJS/ExcelJS boundary, and headless engine comparison.

Useful deeper examples: invoice totals, budget variance alerts, fulfillment capacity plan, quote approval threshold, subscription MRR forecast, agent framework adapters, MCP tool server shape, XLSX formula recalculation in Node, and serverless quote approval. Run npm run quote-approval-api, npm run agent:openai-agents-sdk, npm run agent:framework-adapters, npm run agent:mcp-tools, npm run agent:mcp-transcript, npm run agent:mcp-file-transcript, npm run agent:mcp-stdio, or npm exec --package @bilig/headless@0.40.21 -- bilig-workpaper-mcp when that is the path you are evaluating.

The serverless example also includes npm run next-route-handler, npm run next-server-action, npm run next-server-action-formdata, npm run framework-adapters, and npm run persistence-adapters for framework-specific boundary checks.

The MCP server is also listed in the official registry: https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.proompteng%2Fbilig-workpaper. Clients that support Streamable HTTP MCP can also smoke-test the stateless hosted endpoint at https://bilig.proompteng.ai/mcp; use the local stdio server when the agent needs to persist a project WorkPaper JSON file.

Examples You Can Run

The runnable examples are TypeScript files. Some source imports end in .js because Node ESM resolves compiled package output that way; the files you edit and run are still .ts.

From a cloned checkout:

pnpm --dir examples/headless-workpaper install --ignore-workspace
pnpm --dir examples/headless-workpaper run start
pnpm --dir examples/headless-workpaper run json-records
pnpm --dir examples/headless-workpaper run csv-shaped
pnpm --dir examples/headless-workpaper run invoice-totals
pnpm --dir examples/headless-workpaper run budget-variance
pnpm --dir examples/headless-workpaper run fulfillment-capacity
pnpm --dir examples/headless-workpaper run quote-approval
pnpm --dir examples/headless-workpaper run subscription-mrr
pnpm --dir examples/headless-workpaper run persistence

The most useful entry points:

• JSON records input
• CSV shaped input
• invoice totals
• budget variance alerts
• fulfillment capacity plan
• quote approval threshold
• subscription MRR forecast
• SheetJS, xlsx-populate, and ExcelJS recalculation bridge

For agent tools:

pnpm --dir examples/headless-workpaper run agent:verify
pnpm --dir examples/headless-workpaper run agent:tool-call
pnpm --dir examples/headless-workpaper run agent:openai-agents-sdk
pnpm --dir examples/headless-workpaper run agent:openai-responses
pnpm --dir examples/headless-workpaper run agent:ai-sdk-generate-text
pnpm --dir examples/headless-workpaper run agent:ai-sdk-stream-text
pnpm --dir examples/headless-workpaper run agent:framework-adapters
pnpm --dir examples/headless-workpaper run agent:mcp-tools
pnpm --dir examples/headless-workpaper run agent:mcp-file-transcript
pnpm --dir examples/headless-workpaper run agent:mcp-stdio

The AI SDK example uses ai-sdk-generate-text-tool-smoke.ts. The OpenAI Agents SDK guide is docs/openai-agents-sdk-workpaper-tool.md. The OpenAI Responses guide is docs/openai-responses-workpaper-tool-call.md. The agent framework guide is docs/vercel-ai-sdk-langchain-spreadsheet-tool.md.

The package also ships the MCP stdio binary:

npm exec --package @bilig/headless@0.40.21 -- bilig-agent-challenge
npm exec --package @bilig/headless@0.40.21 -- bilig-formula-clinic ./reduced.xlsx --cells "Summary!B7,Inputs!B2"
npm exec --package @bilig/headless@0.40.21 -- bilig-mcp-challenge
npm exec --package @bilig/headless@0.40.21 -- bilig-workpaper-mcp
npm exec --package @bilig/headless@0.40.21 -- bilig-workpaper-mcp --workpaper ./pricing.workpaper.json --init-demo-workpaper --writable
docker build --target bilig-workpaper-mcp -t bilig-workpaper-mcp:local .

bilig-agent-challenge prints the same edit, formula readback, WorkPaper JSON export, restore, and verified: true proof object used by the agent workbook challenge page.

bilig-mcp-challenge proves the file-backed MCP path end to end: initialize JSON-RPC, list tools/resources/prompts, edit Inputs!B3, read recalculated Summary!B3, export the WorkPaper JSON, restart from disk, and return verified: true.

bilig-formula-clinic imports a reduced XLSX locally, samples formulas, reads requested cells through WorkPaper, and prints a Markdown issue body. It does not upload workbook contents.

Without --workpaper, the binary starts the built-in demo workbook. With --workpaper, it loads your persisted WorkPaper JSON and exposes list_sheets, read_range, read_cell, set_cell_contents, get_cell_display_value, export_workpaper_document, and validate_formula; --writable persists set_cell_contents edits back to the same file. It also exposes MCP resources and prompts for bilig://workpaper/agent-handoff, bilig://workpaper/current-document, edit_and_verify_workpaper, and debug_workpaper_formula, so capable clients can discover the workflow before calling tools. The Docker target is for MCP directory scanners: it seeds a demo WorkPaper JSON inside the image and starts the file-backed --writable tool surface so tools/list, resources/list, and prompts/list return the general WorkPaper agent surface without cloning this monorepo. For remote MCP clients, the app runtime exposes https://bilig.proompteng.ai/mcp as a stateless JSON-only Streamable HTTP endpoint for tool discovery and write/readback smoke tests.

It is published in the official MCP Registry as io.github.proompteng/bilig-workpaper: https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.proompteng%2Fbilig-workpaper. It is also live on Glama with Try in Browser, A-grade tool pages, and all seven file-backed WorkPaper tools: https://glama.ai/mcp/servers/proompteng/bilig.

Proof You Can Reproduce

• The 90-second TypeScript check above edits one input, restores the saved JSON document, and verifies the dependent formula result.
• For a production-shaped evaluator path, run the quote approval WorkPaper API proof. It starts from an empty Node directory, downloads one maintained TypeScript route smoke, writes quote inputs, recalculates an approval decision, persists JSON, and verifies restored readback.
• For an XLSX formula recalculation example, run examples/xlsx-recalculation-node. It imports a generated XLSX pricing workbook, edits input cells, reads the recalculated approval decision, exports XLSX, reimports it, and verifies the formulas survived the round trip. The public decision page is XLSX formula recalculation in Node.js.
• For a shorter public decision page, read formula workbooks for Node services and agent tools. It compresses the WorkPaper boundary, MCP file-backed mode, benchmark caveat, and alternative-tool guidance into one shareable evaluator path.
• For HN, Lobsters, Reddit, or newsletter review, use the Show HN maintainer note. It keeps the empty npm-project command, verified: true output, benchmark caveat, known limits, and feedback ask together.
• Run pnpm workpaper:bench:competitive:check. The checked-in artifact shows 100/100 comparable WorkPaper mean wins and no p95 holdouts; the narrowest p95 win is aggregate-overlapping-sliding-window-wide at 0.946x.
• The benchmark card is generated from that artifact: docs/assets/workpaper-benchmark-card.png.
• Read the compatibility limits before importing real Excel workbooks.
• Use the production adoption checklist before promoting a WorkPaper-backed workflow beyond evaluation.
• For XLSX accuracy audits, use the Excel oracle harness. It separates import success, timeouts, stale cached formula values, and fresh Microsoft Excel recalculation results.
• The WorkPaper MCP server is listed in the official MCP Registry and on Glama. The directory status page keeps the npm command, remote endpoint, static MCP server card, and directory evidence in one place.
• Public feedback threads: workflow questions, service examples, persistence adapters, JavaScript spreadsheet library guide, OpenAI Responses tool calls, and benchmark critique.

If the 90-second check matches a problem you have, star or bookmark the repo: https://github.com/proompteng/bilig/stargazers. If you are evaluating @bilig/headless for production and want release notifications, watch releases: https://github.com/proompteng/bilig/subscription.

XLSX Accuracy Policy

Cached formula values embedded in .xlsx files are cache diagnostics, not an accuracy verdict. A Bilig correctness bug should only be claimed when the expected value came from a fresh Excel recalculation oracle.

OUT=.cache/excel-oracle-evaluation
pnpm workpaper:xlsx-oracle -- prepare-oracle /path/to/xlsx-corpus "$OUT"
pnpm workpaper:xlsx-oracle -- evaluate-cache /path/to/xlsx-corpus "$OUT"
pnpm workpaper:xlsx-oracle -- evaluate-oracle /path/to/xlsx-corpus "$OUT/recalculated" "$OUT"
pnpm workpaper:xlsx-oracle -- summarize "$OUT"

evaluate-cache writes cache-diagnostic.json and stays non-authoritative. evaluate-oracle writes excel-oracle-report.json, and summarize writes summary.md. If Excel automation is unavailable, cells are classified as missing_excel_oracle instead of being promoted to bugs.

What Is In This Repo

• packages/headless: WorkPaper runtime and npm package.
• packages/excel-import: XLSX import/export boundary. Install both packages with pnpm add @bilig/headless @bilig/excel-import when you need file import and export.
• packages/formula: formula parser, binder, compiler, and evaluator.
• packages/core: workbook engine, snapshots, mutation flow, and scheduler.
• packages/grid and apps/web: browser spreadsheet shell.
• apps/bilig: fullstack monolith runtime, API surface, and static asset server.
• packages/renderer: React workbook renderer.
• packages/protocol, packages/binary-protocol, packages/agent-api, and packages/worker-transport: protocol and integration boundaries.
• packages/wasm-kernel: AssemblyScript/WASM numeric fast path.
• packages/benchmarks: benchmark harness and performance contracts.

For XLSX import/export from TypeScript:

import { WorkPaper } from '@bilig/headless'
import { exportXlsx, importXlsx } from '@bilig/excel-import'

Use WorkPaper.buildFromSnapshot(imported.snapshot) after import and workbook.exportSnapshot() before exportXlsx().

Local Development

Use Node 24+, Bun, and pnpm@10.32.1.

pnpm install
pnpm dev:web
pnpm dev:web-local
pnpm dev:sync

For a full local preflight:

pnpm lint
pnpm typecheck
pnpm test
pnpm test:browser
pnpm run ci

Generated sources and public evidence are checked:

pnpm protocol:check
pnpm formula-inventory:check
pnpm workspace-resolution:check
pnpm workpaper:bench:competitive:check
pnpm docs:discovery:check

For Coding Agents

Start with the public package boundary unless the task is explicitly engine work.

1. Read packages/headless/README.md before touching WorkPaper behavior.
2. Read docs/AGENTS.md, docs/skill.md, or docs/llms-full.txt when building an agent-facing integration from outside the repo.
3. Use public exports from @bilig/headless; do not reach into src/ or dist/ when writing consumer examples.
4. Keep examples TypeScript-first.
5. Do not call stale XLSX cached formula values an accuracy oracle.
6. Add focused tests before changing formulas, persistence, range bounds, config rebuilds, events, row/column moves, or sheet lifecycle.
7. Run the focused package tests first, then broaden to pnpm run ci.

Contributing

Read CONTRIBUTING.md before opening a PR. If this is your first patch, start with the new contributor guide and then claim a scoped starter issue.

Good first patches usually fit one of these shapes:

• formula fixtures with clear expected behavior;
• small WorkPaper examples that prove a real service or agent workflow;
• focused correctness fixes with regression tests;
• grid accessibility and keyboard-behavior improvements;
• docs that turn an existing architecture note into a runnable command.

The shortest public on-ramp is the starter issues queue. It keeps code/test picks, example tasks, adapters, and focused docs work in one current list, with small acceptance commands for first patches.

If this is your first contribution to bilig, use the first-timers-only filter.

Security And Support

Read SECURITY.md before sharing vulnerability details, private workbook data, tokens, credentials, or exploit reproductions. Security reports should use GitHub private vulnerability reporting when available, or security@proompteng.ai when the private flow is not visible.

Use SUPPORT.md for the fastest public support path. Good reports include the package version, Node version, OS, exact formula or workbook input, expected value, actual value, and the smallest command or script that reproduces the issue.

CI

Forgejo Actions is the primary CI surface via .forgejo/workflows/forgejo-ci.yml. GitHub Actions mirrors the verification contract in .github/workflows/ci.yml.

The strict gate includes frozen lockfile install, full pnpm run ci, artifact budget checks, browser smoke, and tracked-file cleanliness checks.

License

MIT.