The local MCP server for Stratta: the engineering norms your bureau licensed (SIA, Eurocodes), cited to the section and page, inside any agent that speaks MCP.

Requires a free Stratta account: https://stratta.ch/sign-up.

[!IMPORTANT] Your STRATTA_API_KEY is a secret — it grants read/write access to your Stratta workspace. Never commit it to a repository, paste it into a shared/ project-scoped MCP config, or share it in logs. Prefer a user-scoped config or a shell environment variable. If a key leaks, revoke it immediately under Settings › API keys (https://stratta.ch/settings?tab=keys).

Do you need this package?

Usually not. Stratta also runs as a remote connector — one address, a browser sign-in, no key, no Node:

https://stratta.ch/mcp

That is the shorter path, the one the dashboard walks you through for Claude, ChatGPT, Claude Code, Codex, Cursor, VS Code, Gemini CLI and Windsurf, and the only one that works in an agent running in the cloud (claude.ai, ChatGPT). It serves 58 of the 59 tools below, ingestion included: the pre-pass script is downloaded from https://stratta.ch/ingest-prepass.py when it is not on disk. See https://stratta.ch/docs/en/guides/connect-remote.

This package is what you want when:

your agent cannot open a browser — CI, a scheduled task, a server — and authenticates with an API key instead;
you want add_attachment, the one tool the connector does not serve: it uploads a file from your disk to a project dossier;
you would simply rather run the server yourself.

Install

Claude Code (recommended)

Add the server — no key needed up front:

claude mcp add stratta --scope user -- npx -y @stratta/mcp

--scope user registers it for your user, so the tools are there in every project. Without it, claude mcp add writes to the current folder's config and the server exists nowhere else.

Then sign in. This opens stratta.ch in your browser, where you confirm which machine and organisation to authorise; the key comes back to the terminal on its own and is saved to ~/.stratta/config.json (owner-only, 0600). You never see it, and you only do this once:

npx -y @stratta/mcp login

No browser on this machine — remote server, SSH, CI? login --paste asks for a key from https://stratta.ch/settings?tab=keys instead, without echoing it.

If you skip the step entirely, Claude Code prompts you for a key on the first tool call.

You can also pass the key explicitly as an environment variable (it then takes precedence over the saved key):

claude mcp add stratta --scope user --env STRATTA_API_KEY=sk_strt_xxx -- npx -y @stratta/mcp

Commands

Command	Purpose
`npx -y @stratta/mcp login`	Authorise this machine from your browser
`npx -y @stratta/mcp login --paste`	Paste a key, when there is no browser
`npx -y @stratta/mcp logout`	Remove the key stored on this machine
`npx -y @stratta/mcp whoami`	Which account and workspace this machine speaks as
`npx -y @stratta/mcp doctor`	Diagnose an install that is not responding
`npx -y @stratta/mcp update`	Check your version and fetch the latest
`npx -y @stratta/mcp --help`	All of the above

Run doctor first when norms are missing: a revoked key, a stale STRATTA_API_KEY in your shell and an unreachable backend all look identical from inside the agent, and are fixed differently.

Staying up to date

npx -y @stratta/mcp fetches the published package, but npx caches what it resolved, so a server can keep launching a version npm replaced weeks ago with nothing to tell you.

npx -y @stratta/mcp update

Prints the version you are running and the one npm serves, and fetches the new one if they differ. Restart your agent afterwards. The server also mentions it on stderr at startup when it notices it is behind.

Claude Desktop

npx -y @stratta/mcp login

Then add the server to claude_desktop_config.json (Settings → Developer → Edit Config) — no key needed in the file:

{
  "mcpServers": {
    "stratta": {
      "command": "npx",
      "args": ["-y", "@stratta/mcp"]
    }
  }
}

Restart Claude Desktop. The Stratta tools should appear in the MCP indicator.

Prefer to keep the key in the config instead of ~/.stratta/config.json? Add an "env": { "STRATTA_API_KEY": "sk_strt_xxx" } block to the server entry — but that file then stores the key in plaintext, so keep it private and unsynced.

Global install (optional)

npm install -g @stratta/mcp

Then use "command": "stratta-mcp" instead of npx.

Configuration

The API key is resolved in this order: the STRATTA_API_KEY env var, then ~/.stratta/config.json (written by login or the first-run prompt). Other settings come from environment variables — see .env.example.

Variable	Required	Default	Purpose
`STRATTA_API_KEY`	no¹	–	API key from https://stratta.ch. ¹If unset, the server falls back to `~/.stratta/config.json`, or prompts you on first use (clients that support elicitation).
`STRATTA_CONVEX_URL`	no	Stratta prod backend	Override only if you self-host.

Tests

npm test runs the unit tests. The two integration suites (tests/handlers.test.ts, tests/dossier-flow.e2e.test.ts) run this checkout's built server against the deployment you name, and are skipped when either variable is missing:

npm run build
STRATTA_E2E_URL=https://<dev-deployment>.convex.cloud STRATTA_E2E_API_KEY=sk_strt_... npm test

Point them at a development deployment: the dossier flow creates a dossier named E2E dossier <timestamp> and does not delete it.

Tools exposed

59 tools, generated from one catalogue shared with the remote connector (which serves the same 58, everything minus add_attachment).

Read (10 tools — query the norms of your workspace):

Tool	Purpose
`get_methodology`	Behavioural contract: persona, workflow, meta-routing hints, answer rules. Call first.
`whoami`	Which organisation, role and plan this connection reads as, and how many norms it sees.
`list_norms`	List all norms published in your workspace (code, year, title, language, coverage).
`get_toc`	Hierarchical TOC for a norm (default `maxDepth=1` = chapters).
`get_subtree`	Drill into a chapter/section subtree (`path` + `maxDepth`).
`get_section`	Full enriched content of a section (formulas, tables, figures, cross-refs).
`search_in_norm`	Keyword search inside a norm.
`search_corpus`	Keyword search across every norm of the workspace, grouped by norm.
`get_figure`	Retrieve a figure inline (base64 ImageContent).
`get_cross_refs`	Outgoing cross-refs from a section to other norms.

Site (10 tools — what public Swiss registers know about a plot, and the site sheet as the app shows it):

Tool	Purpose
`scan_site`	Collect municipality, parcel, elevation, geology, nearby boreholes, polluted sites, hazards and noise class around a Swiss address.
`get_site_context`	Read what the scan settled, and — separately — what it could not, with the reason.
`get_boreholes`	Read the boreholes nearest the site with their logged strata, SIA 261 ground class, water table, and links to cantonal documents.
`list_sites`	The site sheets of the organisation, with their dossier, canton and scan status.
`get_site`	The sheet as the app shows it: every fact with its key, status, source, notice and attribution, and the scan with its sources.
`get_site_section`	The section along the axis: terrain, modelled bedrock, geology bands and the boreholes of the corridor with their logs.
`list_site_overlays`	The map areas around the point (polluted sites, hazards, water protection), with distance and coverage of the site point.
`get_groundwater_contours`	The cantonal piezometric contours stored by the scan, with the aquifer name and elevation.
`list_site_photos`	The photos uploaded on the sheet, with position, direction, instant and note. No image, no link.
`list_site_neighbours`	The organisation's other sheets within a radius, with the distance and the geological unit their scan established.

Dossier (25 tools — keep what was decided on a project, and everything the dossier page can do to a question):

Tool	Purpose
`list_dossiers`	Your organisation's dossiers, most recently touched first, with open-question counts and site id.
`open_dossier`	Open a project's dossier, creating it if needed. Idempotent on the name.
`open_question`	Open one question to settle, with optional named options. Idempotent on the title.
`save_finding`	Record one piece of evidence: a cited article, a retained value and why, an observation.
`record_decision`	Settle a question with a decision the engineer has confirmed, and the retained option.
`load_dossier`	Reload everything: questions with their evidence and decisions, open ones first.
`resolve_question`	Close a question without a decision, or reopen one. The evidence stays.
`list_attachments`	The project attachments of a dossier: site reports, borehole logs, minutes, data sheets.
`read_attachment`	Read an attachment's text as Markdown, page by page.
`search_in_dossier`	Full-text search over a dossier's attachments, with the page of each hit.
`add_attachment`	Upload a file from the user's machine to a dossier (PDF, DOCX, XLSX, images, text). Local server only.
`list_templates`	The checklists the organisation wrote for its types of structure.
`apply_template`	Open a template's questions in a dossier and file the clauses that resolve in the corpus.
`draft_deliverable`	Open the document a dossier produces (project basis, use agreement, report) and get its plan and sources.
`write_section`	Write one section of a deliverable with what it rests on; a section without a source is refused.
`list_skills`	The procedures the agent follows for a repeatable task: the ones Stratta ships and the ones the office wrote.
`get_skill`	Read one procedure in full; the office version wins over the Stratta one of the same name.
`list_questions`	The questions of a dossier, paginated, with status, assignee, due date, options and decision title.
`get_question`	One question in full: options, decision, evidence with every citation field, comments with authors.
`get_dossier_activity`	The history of a dossier, most recent first, paginated: who did what, from the app or an agent.
`list_exports`	The verification notes and journals exported from a dossier, with hash and trusted timestamp.
`update_question`	Reword a question, assign it by e-mail address, set or clear its due date.
`add_option`	Add one way of settling a question. Idempotent on the name.
`update_option`	Rename or describe an option, or mark it retained (the others are released).
`delete_option`	Remove an option; its evidence stays on the question. Asks the user first.
`delete_question`	Delete a question opened by mistake; its evidence stays, unfiled. Asks the user first.
`add_comment`	Leave a signed remark on a dossier, a question or an entry.
`update_entry`	Correct an entry's wording, value, confidence or citation in place.
`attach_entry`	File an entry under a question and optionally an option, or unfile it.

A dossier is read, annotated, reviewed and exported from stratta.ch/dossiers.

Ingest (10 tools — add YOUR licensed norms; driven by the bundled ingest-norm skill; owner or admin role):

Tool	Purpose
`ingest_status`	Check if a norm already exists in your workspace, and its coverage.
`ingest_create_document`	Create a draft norm document.
`ingest_create_sections`	Bulk-insert sections (returns `nodeId → sectionId` map).
`ingest_attach_formula`	Attach a LaTeX formula to a section.
`ingest_attach_table`	Attach a structured table `{headers, rows}` to a section.
`ingest_attach_cross_ref`	Attach an explicit cross-ref to another norm.
`ingest_upload_figure`	Upload a figure (base64 PNG/JPEG/WebP, ≤ 8 MB) to a section.
`ingest_normalize_cross_refs`	Auto-detect and rebuild cross-refs from section content.
`ingest_publish`	Score the document and flip it to published; refuses below 30/100 unless forced.
`ingest_delete`	Delete a document and all its children.

How agents should use it

For querying:

Call get_methodology first — load the behavioural contract.
Call list_norms to see what's available in your workspace.
Call get_toc(norm) to navigate the structure; get_subtree to drill in.
Call get_section(norm, path) to read specific content.
Use search_corpus when the norm is unknown, search_in_norm when the section path is.
Follow crossRefs for compound questions (e.g. SIA 261 → SIA 263 → EC).
Call get_figure when the section references a figure relevant to the answer.

Two skills ship in the package: consult-stratta (the working method an agent follows to answer from the norms, generated from the same text the server serves through get_methodology) and ingest-norm.

Resources and prompts

Four stratta:// resources can be pinned to a conversation or read without a tool call, each scoped to your workspace: stratta://norms (JSON), stratta://methodology (Markdown), stratta://norm/{code}/toc (the table of contents to depth 2, code URL-encoded, e.g. stratta://norm/SIA%20267/toc) and stratta://dossier/{id} (a project dossier as Markdown). The same four are served by the remote connector.

Three prompts appear as slash commands in clients that support them: investigate-question (question, project?), resume-dossier (name) and check-value (value, norm?).

For ingesting your own licensed norms, see the bundled ingest-norm skill — a 2-phase hybrid pipeline (since 0.4.0): a Python pre-pass (scripts/ingest-prepass.py, PyMuPDF) extracts the hierarchical tree and rasterizes figures deterministically, then the agent enriches sections with summaries, LaTeX formulas, tables and cross-refs via targeted visual reading. Requires Python ≥ 3.10 with PyMuPDF (python -m pip install --user pymupdf).

Troubleshooting

`Authentication failed` / `Invalid API key`

Verify the key starts with sk_strt_ and is not revoked at https://stratta.ch/settings?tab=keys.
Check the env var is reaching the process: echo $STRATTA_API_KEY (or $env:STRATTA_API_KEY on Windows PowerShell).
If you copied from the UI, make sure no leading/trailing whitespace was added.

`ECONNREFUSED` / network errors

Confirm outbound HTTPS to *.convex.cloud is allowed by your firewall/VPN.
Try curl -I https://stratta.ch to verify general internet reachability.

Tools don't appear in your agent

Restart your Claude client after editing the config.
Check the MCP server logs (Claude Code: claude mcp logs stratta; Claude Desktop: ~/Library/Logs/Claude/mcp-server-stratta.log on macOS).
Make sure your Node.js version is >=20 (node --version).

Rate-limited

Each user can create up to 50 active keys and 20 new keys per 24h. Revoke unused keys in the dashboard.

`QUOTA_EXCEEDED`

Your organization reached one of its limits. The error names the dimension, your current count and the plan limit. Retrying will fail identically.

Limit	Free	Pro	Max	Team
Norms	1	15	60	75
Sections	1,000	15,000	60,000	75,000
Figures	60	750	3,000	3,750
Queries / month	500	15,000	60,000	75,000
Members	1	1	1	5

Beyond the included queries, paid plans bill the overage per thousand. An Enterprise contract scales seats, norms and queries further; the calculator is at https://stratta.ch/tarifs

Stock limits free up when you delete a norm (ingest_delete). The monthly query counter resets on its own. Gauges live on the Workspace page of your dashboard, and an org admin can also set caps below the plan. Full details: https://stratta.ch/docs/en/account/plans

License

Proprietary — © Stratta, Lausanne. All rights reserved. This package is the official Stratta MCP client; redistribution, modification, or reuse of the source is not permitted without prior written consent.