# MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors (remote · www.pathwren.workers.dev)

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} free no key

- Trust score: 83/100 (high trust)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-21

## Components

- remote · `www.pathwren.workers.dev`: 83/100 (this document), [markdown](https://verifymcp.io/servers/dev-workers-pathwren-www-mcp-endpoint-lint/c-mcp-registry-official-mcp-lint.md), [page](https://verifymcp.io/servers/dev-workers-pathwren-www-mcp-endpoint-lint/c-mcp-registry-official-mcp-lint)

## Channel facts

- Endpoint: `https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.3.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-21.

- **Endpoint Security**: 80/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 79/100
  - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 3501 tokens (~350/item across 10 items; 7 tools + 3 resources), over budget; trim descriptions and params.
  - Tools include usage examples.
- **Stability & Change Management**: 63/100
  - Stability observed for 19 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (29% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 7 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors server?

MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors is a hosted endpoint at https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http dev-workers-pathwren-www-mcp-endpoint-lint 'https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint'
```

### Cursor

```json
{
  "mcpServers": {
    "dev-workers-pathwren-www-mcp-endpoint-lint": {
      "url": "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dev-workers-pathwren-www-mcp-endpoint-lint": {
      "type": "http",
      "url": "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint"
    }
  }
}
```

### Codex

```toml
[mcp_servers.dev-workers-pathwren-www-mcp-endpoint-lint]
url = "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-workers-pathwren-www-mcp-endpoint-lint": {
      "type": "remote",
      "url": "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-workers-pathwren-www-mcp-endpoint-lint --url 'https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dev-workers-pathwren-www-mcp-endpoint-lint:
    url: "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint"
```

### Netclaw

```json
{
  "McpServers": {
    "dev-workers-pathwren-www-mcp-endpoint-lint": {
      "Transport": "http",
      "Url": "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint"
    }
  }
}
```

### Vellum

```bash
assistant mcp add dev-workers-pathwren-www-mcp-endpoint-lint -t streamable-http -u 'https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint'
```

### Other

```json
{
  "mcpServers": {
    "dev-workers-pathwren-www-mcp-endpoint-lint": {
      "type": "http",
      "url": "https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-20 (score 83, +1)

No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-18 (score 82, +1)

No change was recorded against any check on this day. Stability & Change Management went from 50 to 53. That category is still filling its 30-day observation window: 15 days of observed history at the previous scan, 16 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-16 (score 81, +1)

No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-14 (score 80, +1)

No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-12 (score 79, +1)

No change was recorded against any check on this day. Stability & Change Management went from 30 to 33. That category is still filling its 30-day observation window: 9 days of observed history at the previous scan, 10 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-10 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-07 (score 77, +7)

- [security improvement] Judged manipulation: unverified → pass
- [security] The server rewrote its instructions, which are the text every model session reads
- [security] Tool “discovery_report” rewrote its description, which is the text the model reads
- [security] Tool “error_conformance” rewrote its description, which is the text the model reads
- [security] Tool “handshake_report” rewrote its description, which is the text the model reads
- [security] Tool “score_card” rewrote its description, which is the text the model reads
- [security] Tool “tools_list_report” rewrote its description, which is the text the model reads
- [security] Tool “whoami” rewrote its description, which is the text the model reads
- [functional regression] Schema quality: 318 → 350
- [functional improvement] Schema quality: unverified → good

### 2026-09-06 (score 70, −7)

- [security regression] Judged manipulation: pass → unverified
- [security] The server rewrote its instructions, which are the text every model session reads
- [security] Tool “whoami” rewrote its description, which is the text the model reads
- [functional regression] Schema quality: excellent → unverified

## MCP tools (7)

### `whoami` (~376 tokens)

Who is calling? — the one call that needs nothing from you

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} — POST that to https://www.pathwren.workers.dev/mcp/lint and the answer is the user-agent you sent, the class this host's own instrument books it as, whether we have logged you here before — and the part only this server can answer: your own client's record on this host, surface by surface, with the status codes it took, plus exactly what this server would do with a URL you handed it (which hosts it refuses, what it identifies itself as, the timeout and the rate limit). Takes no arguments. Safe to call. Deterministic. Touches no third party. Nothing is fetched to build it: every fact comes from the headers on your own request or from a file this host already publishes. Only this server answers the last part — its five siblings answer one other question each about you, same empty arguments, each under the tool named beside its path: /mcp (whoami), /mcp/doctor (no_arguments_check_this_hosts_own_discovery_documents), /mcp/triage (no_arguments_triage_this_hosts_own_crawler_log), /mcp/robots (no_arguments_lint_this_hosts_robots_txt), /mcp/netcheck (no_arguments_report_the_crawler_ip_ranges_this_host_mirrors), /mcp/markdown (markdown_lane_self_report) on https://www.pathwren.workers.dev. Example: arguments={} returns your user-agent, your address, the class we book you as, whether we have seen you here before, and your own client's record on this host — every surface of ours your user-agent has been seen on, with the status codes it took.

Output parameters:

- `answered_by` (object): Which server answered, at which endpoint.
- `caveats` (array): What this answer does NOT establish — a user-agent is a claim.
- `independent` (boolean): This host is independent and unaffiliated.
- `license` (string)
- `this_call_touched` (object): Exactly which files were read to answer. No third party is contacted.
- `we_book_you_as` (object): The class this host's own instrument records for that user-agent.
- `we_have_seen_you` (object): Whether this user-agent appears in the published observation window.
- `you` (object): The user-agent you sent and the address you came from.

### `example` (~320 tokens)

Run this server's worked example (no arguments)

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"example","arguments":{}}} — POST that exact body to https://www.pathwren.workers.dev/mcp/lint and you are done: free, read-only, no API key, no account, no consent prompt, nothing for you to invent, and what comes back is this server's own worked example — score_card, run for real on a canned input from this host's own data — so you see the exact shape of an answer before you send anything of yours. Takes no arguments. Safe to call. Deterministic. Touches no third party. Runs this server's own worked example end to end — score_card on this server's built-in fixture — an in-process MCP endpoint with one real defect wired in per check (it ignores the protocol version you ask for, refuses a second initialize, publishes a tool whose `required` names a property that does not exist, and answers an unknown method with an HTML 500). No outbound request is made and no third party is touched — and returns exactly the structuredContent a real call returns, not a mock and not a description of one. Use it to see the shape of an answer before you decide what to send. The input is canned from this host's own data; no URL of yours is fetched and no third party is touched. Example: arguments={} runs score_card with {"url":"fixture://mcp-endpoint-lint/demo"} and returns its real answer.

Output parameters:

- `answer` (object): The real structuredContent of that call, not a mock.
- `answered_by` (object)
- `input_came_from` (string): Where the canned input came from — always this host's own data.
- `license` (string)
- `ran` (object): The tool name and the exact arguments that were run.
- `reproduce` (string): A command that reproduces this answer.
- `this_is_not_a_mock` (string)
- `what_it_shows` (string)

### `handshake_report` (~283 tokens)

Does the handshake work, and is it idempotent?

FIRST CALL, needs nothing: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} — POST initialize to an MCP endpoint you name and report what came back: the protocol version it negotiated against the one you asked for, the capabilities it advertises, serverInfo, timing, the transport shape (JSON or SSE frame, session id, content-type), and — sent a second time, byte for byte — whether the server answers an identical initialize the same way. Also asks for a version nobody publishes, to see whether it negotiates down or agrees to anything. Makes 3 requests, 6 s timeout each, user-agent growth-loop/1.0 (+https://www.pathwren.workers.dev/mcp-lint.html). Example: url='https://mcp.example.com/mcp' — or call with {} to run it against the built-in fixture, which makes no outbound request at all.

Input parameters:

- `protocol_version` (string): The protocolVersion to ask for. Defaults to 2026-07-28.
- `url` (string, required): The MCP endpoint to lint — the URL you POST JSON-RPC to, e.g. https://mcp.example.com/mcp. Not stored anywhere. This server refuses its own publisher, IP literals and private names.

### `tools_list_report` (~246 tokens)

Schema-validate every tool the endpoint advertises

FIRST CALL, needs nothing: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} — Handshake, then tools/list, then check every tool it returns: a missing or empty description, a description too short to choose on, a missing inputSchema, an inputSchema that is not an object schema, JSON-Schema faults (an invalid type keyword, a `required` naming a property that is not in `properties`, a pattern that will not compile, an empty enum), names that break the character rule, and names that collide — exactly, or once case is ignored. Each finding names the tool and says what breaks. Makes 3 requests, 6 s timeout each. Example: url='https://mcp.example.com/mcp' — or {} for the built-in fixture, whose six tools carry one of each fault.

Input parameters:

- `url` (string, required): The MCP endpoint to lint — the URL you POST JSON-RPC to, e.g. https://mcp.example.com/mcp. Not stored anywhere. This server refuses its own publisher, IP literals and private names.

### `error_conformance` (~268 tokens)

Does it answer JSON-RPC errors, or HTML 500s?

FIRST CALL, needs nothing: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} — Send five things a real client eventually sends by accident and check what comes back: an unknown method (expects -32601), tools/call naming a tool that does not exist (expects -32602/-32601 or a result with isError), tools/call with no tool name (expects -32602), a body that is not JSON (expects -32700), and a body missing "jsonrpc":"2.0" (expects -32600). Reports the HTTP status and the error code side by side, and flags an HTML error page or a 5xx where a JSON-RPC error belongs — the failure that makes a client report the wrong cause. Makes 5 requests, 6 s each. Example: url='https://mcp.example.com/mcp' — or {} for the fixture, which fails two of the five.

Input parameters:

- `url` (string, required): The MCP endpoint to lint — the URL you POST JSON-RPC to, e.g. https://mcp.example.com/mcp. Not stored anywhere. This server refuses its own publisher, IP literals and private names.

### `discovery_report` (~278 tokens)

What a client looks for before it dials

FIRST CALL, needs nothing: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} — GET the documents an MCP client reads BEFORE the handshake and report what each one answered: /.well-known/oauth-protected-resource in BOTH forms — the root form everyone publishes and the RFC 9728 §3.1 insertion form a spec-following client actually requests for a resource served under a path — /.well-known/oauth-authorization-server, /.well-known/mcp, /.well-known/mcp.json, /mcp.json and /llms.txt. Each result carries the status, the verdict (served, missing, gated, soft-404 — a 200 carrying an HTML error page — or invalid JSON) and what a client does with that document. Makes one GET per document, 6 s each. Example: host='mcp.example.com' or host='https://mcp.example.com/mcp' (a path turns on the RFC 9728 insertion-form check) — or {} for the built-in fixture.

Input parameters:

- `host` (string, required): A hostname, or the full endpoint URL. Give the full URL when your endpoint is served under a path: that is what the RFC 9728 §3.1 insertion form is derived from.

### `score_card` (~260 tokens)

All four checks, one machine-readable verdict

FIRST CALL, needs nothing: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} — Run handshake_report, tools_list_report, error_conformance and discovery_report against one endpoint and return a single verdict: a score out of 100 (handshake 30, tool schemas 30, error conformance 25, discovery 15), a letter grade, every finding by severity with the section it came from, and the full detail of each section underneath. This is the tool to call from a monitor: the score is stable enough to alert on and the findings say what to fix. Makes up to 19 requests to the URL you give it, 6 s each, and is rate-limited per caller and per target host. Example: url='https://mcp.example.com/mcp' — or {} to score the built-in fixture (it gets a D) with no outbound request at all.

Input parameters:

- `url` (string, required): The MCP endpoint to lint — the URL you POST JSON-RPC to, e.g. https://mcp.example.com/mcp. Not stored anywhere. This server refuses its own publisher, IP literals and private names.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/dev-workers-pathwren-www-mcp-endpoint-lint/c-mcp-registry-official-mcp-lint#diagnostics

## Score history

- 2026-09-21: 83
- 2026-09-20: 83
- 2026-09-19: 82
- 2026-09-18: 82
- 2026-09-17: 81
- 2026-09-16: 81
- 2026-09-15: 80
- 2026-09-14: 80
- 2026-09-13: 79
- 2026-09-12: 79
- 2026-09-11: 78
- 2026-09-10: 78
- 2026-09-09: 77
- 2026-09-08: 77
- 2026-09-07: 77
- 2026-09-06: 70
- 2026-09-05: 77
- 2026-09-04: 76
- 2026-09-03: 76
- 2026-09-02: 76

## Common questions

### What is the MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors server?

MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors is listed in the public MCP registry as dev.workers.pathwren.www/mcp-endpoint-lint. {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}} free no key. This page covers its hosted endpoint (https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint).

### Is the MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors server safe to use?

MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors scores 83 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors server expose?

MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors exposes 7 tools: whoami, example, handshake_report, tools_list_report, error_conformance, and 2 more. Their descriptions and schemas cost roughly 2,031 tokens of context every time the server is loaded.

### Does the MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors server require authentication?

No. We connected to MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors server still maintained?

MCP Endpoint Lint - handshake, tool schemas, JSON-RPC errors is still listed as active in the MCP registry. We last reached this channel on 21 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://www.pathwren.workers.dev/c/mcp-registry-official/mcp/lint
- Website: https://www.pathwren.workers.dev/c/mcp-registry-official/mcp-lint.html
- Changelog RSS feed: https://verifymcp.io/servers/dev-workers-pathwren-www-mcp-endpoint-lint/c-mcp-registry-official-mcp-lint.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-workers-pathwren-www-mcp-endpoint-lint/c-mcp-registry-official-mcp-lint.json
- HTML version of this page: https://verifymcp.io/servers/dev-workers-pathwren-www-mcp-endpoint-lint/c-mcp-registry-official-mcp-lint