Documentation

Everything needed to connect MCP Connector Lint and to reproduce every check locally.

Connect

Remote MCP endpoint: https://mcp-lint.superintelligencesystems.ca/mcp (Streamable HTTP, JSON responses, no authentication).

In Claude, add a custom connector with that URL, then confirm three tools appear: validate_manifest, check_tool_annotations and lint_listing_text. Any MCP client that speaks Streamable HTTP can use the same endpoint.

Tool input

validate_manifest

{
  "manifest": {
    "name": "Example Connector",
    "url": "https://api.example.com/mcp",
    "transport": "streamable-http",
    "authentication": "none",
    "service_domain": "example.com",
    "tools": [ /* tools/list entries or simplified objects */ ],
    "listing": { /* optional listing draft; checked with lint_listing_text rules */ }
  },
  "expect": "read-only"
}

check_tool_annotations

{ "tools": [ /* raw tools/list entries, or simplified objects with top-level readOnlyHint */ ], "expect": "read-only" }

lint_listing_text

{
  "listing": {
    "name": "Example Connector",
    "one_liner": "Checks a connector before it is submitted to the directory.",
    "description": "Long description, up to 2,000 characters.",
    "categories": ["Developer tools"],
    "docs_url": "https://example.com/docs",
    "privacy_url": "https://example.com/privacy",
    "support_contact": "support@example.com",
    "reviewer_note": "No account needed",
    "icon_url": "https://example.com/icon.png",
    "slug": "example-connector",
    "authentication": "none"
  }
}

Output

{
  "ok": false,
  "verdict": "fail",
  "ruleset": "2026-11-03.1",
  "summary": { "errors": 2, "warnings": 1, "infos": 0 },
  "findings": [
    { "rule": "MNF-008", "severity": "error", "path": "manifest.url",
      "message": "host \"localhost\" is a loopback or private address",
      "fix": "Publish the server on a public HTTPS hostname." }
  ],
  "guidance": "Fix the 2 blocking errors before submitting. Warnings are advisory, but each one is the kind of thing a reviewer notices."
}

ok is false only when there is a blocking error. Findings are sorted and de-duplicated, so identical input produces identical output. A validation failure is a result, not an error: the call succeeds and returns the report.

Rules

58 deterministic rules across the three tools. The rationale column cites the directory requirement each rule encodes.

Rule	Severity	Check	Why
`MNF-001`	error	Manifest must be a JSON object	Every other check needs named fields; an array or scalar has none.
`MNF-002`	error	Server name is required	The directory shows the server name and reviewers use it to identify the connector.
`MNF-003`	warning	Server name over 100 characters	The listing name field is capped at 100 characters; a longer server name will not fit it.
`MNF-004`	error	Local transport cannot be listed	The directory requires a remote server; stdio or local-only transports are refused.
`MNF-005`	warning	SSE transport is legacy	Streamable HTTP is the current remote transport; SSE still works but is the older spec revision.
`MNF-006`	error	Remote URL is required	The portal's first step asks for the connector URL; there is nothing to scan without it.
`MNF-007`	error	URL must use HTTPS	Connector URLs must be remote HTTPS; plain HTTP and WebSocket URLs are refused.
`MNF-008`	error	URL points at a loopback or private host	A localhost or RFC 1918 address is not reachable by the reviewer's machine or the portal scan.
`MNF-009`	error	Static bearer token authentication blocks listing	Directory auth is OAuth 2.0 for account-scoped tools or none for public data; a static token is refused.
`MNF-010`	warning	Authentication mode is missing or unrecognised	The portal asks how users sign in, so the manifest should state none or OAuth 2.0 explicitly.
`MNF-011`	error	Manifest must expose at least one tool	A connector with no tools has no review surface and no reason to be listed.
`MNF-012`	warning	First-party service domain is not declared	The directory requires the server to call its own first-party API; declaring the service domain makes that checkable.
`MNF-013`	error	Server URL does not match the declared service domain	The server domain must match the service it fronts; a mismatch is how proxy servers get refused.
`MNF-014`	warning	Manifest and listing names differ	Reviewers match the connector to its listing; two different names for one product read as two products.
`ANN-001`	error	Tool entry is not an object	tools/list returns objects; anything else cannot carry a name or annotations.
`ANN-002`	error	Tool name is required	An unnamed tool cannot be called or reviewed.
`ANN-003`	error	Tool name over 64 characters	The directory caps tool names at 64 characters, snake_case or kebab-case.
`ANN-004`	warning	Tool name is not snake_case or kebab-case	The directory accepts snake_case or kebab-case names; spaces and mixed case are flagged in review.
`ANN-005`	error	Tool title is required	The portal flags tools whose title is missing; the title is the human label shown to users.
`ANN-006`	warning	Tool title is long	Titles are labels; a long sentence is hard to scan in the connector's tool list.
`ANN-007`	error	Tool description is required	The description is what the model reads to decide when to call the tool.
`ANN-008`	warning	Tool description is very short	A description under 20 characters cannot state what the tool returns.
`ANN-009`	error	Tool has no side-effect annotation	Every tool must set readOnlyHint true, or destructiveHint, so clients know what it does.
`ANN-010`	error	readOnlyHint and destructiveHint are both true	The two hints contradict each other; clients use them to decide whether to ask for confirmation.
`ANN-011`	warning	Tool character is ambiguous	readOnlyHint false with destructiveHint false says the tool acts on data but hides what kind of action it takes.
`ANN-012`	warning	inputSchema is missing or not an object schema	MCP expects an object JSON Schema so clients can validate arguments and render them.
`ANN-013`	warning	Description contains instructions to the model	Tool descriptions describe the tool; hidden instructions or prompt-injection phrasing are refused in review.
`ANN-014`	warning	Description contains a URL, contact or promotion	Cross-promotion and contact details belong in listing fields, not tool descriptions.
`ANN-015`	warning	Write-verb name is marked read-only	A create/update/delete style name with readOnlyHint true is a contradiction a reviewer will test.
`ANN-016`	warning	Read-verb name is marked destructive	A get/list style name with destructiveHint true is a contradiction a reviewer will test.
`ANN-017`	error	Duplicate tool name	tools/list must be unambiguous; duplicate names make a call target undefined.
`ANN-018`	error	Destructive tool in a read-only connector	The caller declared the connector read-only, so a destructive tool is a contract mismatch.
`LST-001`	error	Listing name is required	The portal cannot save a listing without a name.
`LST-002`	error	Listing name over 100 characters	The directory caps the listing name at 100 characters.
`LST-003`	warning	Listing name has stray whitespace	Leading, trailing or doubled spaces are invisible in review and look careless in the directory.
`LST-004`	error	One-liner is required	The portal asks for a one-liner; it is the line that appears under the name.
`LST-005`	error	One-liner over 200 characters	The directory caps the one-liner at 200 characters.
`LST-006`	warning	One-liner is very short	Under 20 characters the one-liner cannot say what task the connector completes.
`LST-007`	error	Description is required	The description is where the listing explains what each tool does and what it does not do.
`LST-008`	error	Description over 2,000 characters	The directory caps the description at 2,000 characters.
`LST-009`	warning	Description is thin	Under 200 characters rarely covers what each tool does, who it is for and what it does not do.
`LST-010`	error	Categories must number 1 to 5	The listing accepts one to five categories.
`LST-011`	warning	Categories contain duplicates or empty values	A repeated or blank category is a form error reviewers have to sort out.
`LST-012`	error	Documentation URL is required	The portal requires a documentation URL, and it must resolve.
`LST-013`	error	Documentation URL is not HTTPS	Documentation links are fetched by reviewers; plain HTTP or a malformed URL fails the check.
`LST-014`	error	Privacy-policy URL is required	The portal requires a privacy-policy URL for every connector.
`LST-015`	error	Privacy-policy URL is not HTTPS	The privacy link is clicked in review; plain HTTP or a malformed URL fails the check.
`LST-016`	error	Support contact is required	The listing must name a support route a user can actually reach.
`LST-017`	warning	Support contact looks like a placeholder	example.com, todo and tbd addresses do not reach anyone.
`LST-018`	warning	Unverifiable superlative in the copy	Superlatives such as best or world-class are not checkable and draw reviewer questions.
`LST-019`	warning	Contact details inside listing text	The directory asks for contact details in their own fields, not inside the name, one-liner or description.
`LST-020`	warning	Instructions to the model inside listing text	Listing copy is read by people; instruction or prompt-injection phrasing is refused in review.
`LST-021`	warning	Slug is missing or invalid	The slug is permanent once published; it should be lowercase, hyphenated and short.
`LST-022`	warning	Icon is missing	The listing asks for an icon; a connector without one ships an unfinished card.
`LST-023`	error	Icon URL is not HTTPS	Icons should be served over HTTPS; a malformed or insecure icon URL fails the asset check.
`LST-024`	warning	Authless listing has no reviewer note	For authless connectors the portal asks for a note such as "no account needed"; leaving it blank stalls review.
`LST-026`	error	Listing payload is not a JSON object	The listing fields are read by name; an array or scalar has none.
`LST-025`	warning	Reviewer note mentions credentials for an authless connector	If the connector needs no account, a note containing a password or token contradicts it.

Limits

Request body: 256 KB maximum (413 above that).
Tools per call: 200 maximum (checked by check_tool_annotations and validate_manifest).
The MCP endpoint is stateless: every POST is a complete JSON-RPC exchange, no session to expire.
GET streaming is not supported; POST JSON-RPC to /mcp.

REST API

Same engine, same report, for testing outside an MCP client:

POST /api/v1/validate-manifest
POST /api/v1/check-tool-annotations
POST /api/v1/lint-listing-text
GET  /health
GET  /rules

The request body is the tool argument object shown above. Responses are application/json; errors are {"error":{"code":"…","message":"…"}} with a 4xx status and an actionable message.

Run it locally

npm install
npm test          # deterministic suite
npm run dev       # wrangler dev, http://localhost:8787
npm run typecheck

Source and issue tracker: https://github.com/devops-gm88/mcp-connector-lint.