datuma_k

datuma_k MCP

stdio MCP server for agents using the installed datuma_k binary in an app repo. It does not link the compiler crate. Set DATUMA_K to the binary if it is not on PATH.

Install

Published to npm as @marthvon/datuma-k-mcp and to the MCP Registry as io.github.marthvon/datuma-k.

Cursor / Claude example (mcp.json):

{
  "mcpServers": {
    "datuma_k": {
      "command": "npx",
      "args": ["-y", "@marthvon/datuma-k-mcp"]
    }
  }
}

datuma_k must be on PATH. If it is not, point DATUMA_K at the binary:

{
  "mcpServers": {
    "datuma_k": {
      "command": "npx",
      "args": ["-y", "@marthvon/datuma-k-mcp"],
      "env": {
        "DATUMA_K": "/ABS/PATH/TO/datuma_k/target/release/datuma_k"
      }
    }
  }
}

From source

cd mcp
npm install
npm run build

Then use "command": "node" with "args": ["/ABS/PATH/TO/datuma_k/mcp/dist/index.js"].

The process cwd should be the datuma_k project (the directory with .env), or pass root on each tool call.

Tools

Tool	Binary	Notes
list_project	(files + .env)	Directories and contract/template paths
query_contracts	datuma_k catalog	Optional trait / model / field / attribute / type
validate	datuma_k check	Parse + data/keywords.md required
preview	datuma_k preview	Plan without writing
generate	datuma_k run	Writes generated spans
advise_ngin	(local rules)	When to use ngin vs handwritten code
infer_patterns	catalog + keywords.md	Traits, widgets, association review notes, sync risks, aliases

Resources

• datuma://language/dtct
• datuma://language/ngin
• datuma://language/standards
• datuma://docs/keywords
• datuma://docs/practices
• datuma://docs/when-ngin

Prompts

add-model, add-field, scaffold-ngin, should-use-ngin, infer-contract-patterns

Tests

npm test

Publishing

Two registries, in this order. npm hosts the tarball; the MCP Registry hosts only metadata and verifies it against the published npm package, so npm must go first or the second publish fails with Registry validation failed for package.

Name	Where	Set in
@marthvon/datuma-k-mcp	npm package	package.json name
io.github.marthvon/datuma-k	MCP Registry server	package.json mcpName and server.json name — these two must match, or the registry rejects the publish

The io.github.marthvon/ prefix is not cosmetic: GitHub device-flow auth only grants that namespace. A different prefix needs DNS or HTTP auth.

One-time setup

brew install mcp-publisher            # or a binary from the registry releases page
npm login                             # npm account, scope @marthvon

npm requires 2FA to publish. If the account does not have it, npm publish fails with 403 ... Two-factor authentication or granular access token with bypass 2fa enabled is required, before it ever looks at the tarball. Check with npm profile get; enable with npm profile enable-2fa auth-and-writes or on npmjs.com, and keep the recovery codes.

Release

Bump the version in three places — the registry rejects a version it has already seen, and a mismatch between the npm package version and server.json packages[0].version fails verification:

• package.json → version
• server.json → version
• server.json → packages[0].version

Then:

npm test                              # tsc + node --test
mcp-publisher validate                # checks server.json against the live registry, publishes nothing
npm publish --otp=123456              # prepublishOnly runs the build; drop --otp to be prompted
mcp-publisher login github            # device code → github.com/login/device
mcp-publisher publish

mcp-publisher login persists a token, so day-to-day releases are npm publish then mcp-publisher publish.

Verify:

npm view @marthvon/datuma-k-mcp version
curl "https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.marthvon/datuma-k"

What ships

files in package.json limits the tarball to dist, resources, and README.md. resources/ is required at runtime — server.ts resolves it as dist/../resources — so dropping it from files produces a package that installs cleanly and fails on every resource read. Confirm with npm pack --dry-run before publishing.

Troubleshooting

Error	Cause
403 ... Two-factor authentication ... is required	2FA disabled on the npm account. See above.
403 ... you do not have access	The @marthvon scope belongs to an org; confirm membership with npm org ls marthvon.
Registry validation failed for package	npm publish did not happen yet, or mcpName in package.json does not match name in server.json.
Invalid or expired Registry JWT token	Re-run mcp-publisher login github.
You do not have permission to publish this server	Server name does not start with io.github.<your-github-username>/.
expected length <= 100 on body.description	server.json description is capped at 100 characters. The npm description is not.