# Surface Contract: how platform APIs really behave (remote · penny-surface-contract.penny-mcamp.workers.dev)

Evidence-cited machine-readable contracts for how agent platform APIs really behave

- Trust score: 57/100 (low)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-18

## Components

- remote · `penny-surface-contract.penny-mcamp.workers.dev`: 57/100 (this document), [markdown](https://verifymcp.io/servers/dev-workers-penny-mcamp-penny-surface-contract-surface-contract/penny-surface-contract.md), [page](https://verifymcp.io/servers/dev-workers-penny-mcamp-penny-surface-contract-surface-contract/penny-surface-contract)

## Channel facts

- Endpoint: `https://penny-surface-contract.penny-mcamp.workers.dev/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `2026.10.13`

## 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 2026-10-18.

- **Endpoint Security**: 46/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 7 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS enforcement could not be verified: the plaintext port answered with HTTP 404, which proves neither a plaintext path nor enforcement.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - 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**: 65/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 1177 tokens (~168/item across 7 items; 7 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 13/100
  - Stability observed for 4 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 88/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 64% of tool parameters carry a description.
- **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 8 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 60/100
  - Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28.

## Install

### How do I install the Surface Contract: how platform APIs really behave MCP server?

Surface Contract: how platform APIs really behave is a hosted endpoint at https://penny-surface-contract.penny-mcamp.workers.dev/mcp, 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-penny-mcamp-penny-surface-contract-s 'https://penny-surface-contract.penny-mcamp.workers.dev/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "dev-workers-penny-mcamp-penny-surface-contract-s": {
      "url": "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dev-workers-penny-mcamp-penny-surface-contract-s": {
      "type": "http",
      "url": "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.dev-workers-penny-mcamp-penny-surface-contract-s]
url = "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-workers-penny-mcamp-penny-surface-contract-s": {
      "type": "remote",
      "url": "https://penny-surface-contract.penny-mcamp.workers.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-workers-penny-mcamp-penny-surface-contract-s --url 'https://penny-surface-contract.penny-mcamp.workers.dev/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dev-workers-penny-mcamp-penny-surface-contract-s:
    url: "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "dev-workers-penny-mcamp-penny-surface-contract-s": {
      "Transport": "http",
      "Url": "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add dev-workers-penny-mcamp-penny-surface-contract-s -t streamable-http -u 'https://penny-surface-contract.penny-mcamp.workers.dev/mcp'
```

### Other

```json
{
  "mcpServers": {
    "dev-workers-penny-mcamp-penny-surface-contract-s": {
      "type": "http",
      "url": "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
    }
  }
}
```

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.

### 2026-10-16 (score 57, +1)

- [security] The server rewrote its instructions, which are the text every model session reads
- [security] Tool “contribute_discrepancy” rewrote its description, which is the text the model reads
- [functional regression] Schema quality: pass → fail
- [functional improvement] Tool coverage: 40% → 64%
- [functional] New tool “prepay_check”
- [cosmetic] “contribute_discrepancy” added an optional parameter “observedAt”
- [cosmetic] “contribute_discrepancy” added an optional parameter “reporter”
- [cosmetic] “contribute_discrepancy” reworded the description of “contractId”

### 2026-10-15 (score 56, +1)

- [security] The server rewrote its instructions, which are the text every model session reads
- [functional regression] Schema quality: 64 → 107
- [functional improvement] Tool coverage: 25% → 40%
- [functional improvement] Stability: unverified → 0.03
- [functional] New tool “preflight_mcp_server”

### 2026-10-14 (score 55)

First indexed and scored.

## MCP tools (7)

### `list_surface_contracts` (~26 tokens)

List the platform surface contracts published in Penny's free registry, with claim counts.

### `get_surface_contract` (~75 tokens)

Get the machine-readable surface contract for a platform host (read/write semantics, pending states, rate limits, limits, idempotency, pagination completeness, data portability), each claim carrying its evidence and its verification status.

Input parameters:

- `id` (string, required): contract id or host, e.g. moltbook or www.moltbook.com

### `verify_surface` (~39 tokens)

Run the anonymous conformance checks for a contract now and return verified / failed / unknown / manual / unsupported per claim.

Input parameters:

- `id` (string, required)

### `contribute_discrepancy` (~318 tokens)

Report a platform behaviour that contradicts a published claim, or a new claim, with evidence. One-line call: POST /v1/contribute with {contractId, kind, statement, evidence[], reporter, observedAt}. Stored as pending; a published contract is never changed without independent verification. A contractId no published contract serves is accepted as a NEW-PLATFORM PROPOSAL: the 202 body carries contractExists:false (with proposal:true, proposedContractId and proposedHost), it is listed distinctly at GET /v1/contributions, and it stays pending until a second party reproduces it - it never creates or mutates a contract. A proposal filed by us reads selfProbe:true in that listing, and GET /v1/contributions counts proposals filed by non-self submitters separately from our own self-probes, so only the non-self number is outside coverage.

Input parameters:

- `claimId` (string)
- `contractId` (string, required): the platform's contract id or host; an id no published contract serves is accepted as a new-platform proposal (contractExists:false)
- `evidence` (array, required)
- `kind` (string, required)
- `observedAt` (string): ISO 8601 date you observed the behaviour; a claim without a date is not a measurement
- `reporter` (string): your agent or operator name, so the record is attributed to you and is not read as one of ours (an unattributed record is counted non-self AND flagged noReporter)
- `statement` (string, required)

### `get_integration_recipe` (~77 tokens)

Get a plain-text integration recipe for a platform: the order of operations to use it, and a guard clause for every behaviour we measured going wrong, each naming the contract claim behind it. Derived from the contract, so it cannot drift from it.

Input parameters:

- `id` (string, required): contract id or host, e.g. moltbook

### `preflight_mcp_server` (~252 tokens)

Run the anonymous MCP handshake against ANY https MCP endpoint you name, right now, and get back a verdict (open / refused / unreachable / initialize-transport-error), the shape of any refusal body, whether the server is stateful (sets Mcp-Session-Id), how many tools tools/list returns, and the guard clauses that follow. Use it before wiring an MCP server into your own config. Pass `urls` (up to 5) to check a whole mcp.json in one call. When the endpoint refuses, it also reports whether the refusal advertises a credential path (an RFC 9728 resource_metadata pointer) and whether that pointer resolves to a metadata document naming an authorization server, so you learn where a token would come from without writing that parsing yourself. No credential is sent, none is obtained, and none of their tools is ever called.

Input parameters:

- `url` (string): absolute https URL of the MCP endpoint, e.g. https://host/mcp
- `urls` (array): batch form: 2 to 5 absolute https URLs, checked with the same battery in one call (each one counts against the same daily egress budget as a single preflight)

### `prepay_check` (~237 tokens)

Check an x402 route BEFORE you pay it. GET /v1/prepay?url=<the route> makes ONE unpaid GET with no payment header and no credential, and returns one row: the measured HTTP status, the parsed x402 v2 challenge (scheme / network / asset / amount / payTo), whether that challenge is schema-valid exact-on-Base, and whether its payTo and price agree with the seller's own card (pass `card` to read that card with one more unpaid GET). No payment is made, no credential is sent, no redirect is followed, and a transport failure on our side is reported as unknown rather than as a fact about the seller. Use it to gate a payment decision on measured terms instead of on a seller's prose.

Input parameters:

- `card` (string): optional: absolute https URL of the seller's own card/listing page, read with one more unpaid GET to compare the wallet and the price it advertises (agreement is true|false|unknown, and unknown is nu…
- `url` (string, required): absolute https URL of the route you are about to pay

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/dev-workers-penny-mcamp-penny-surface-contract-surface-contract/penny-surface-contract#diagnostics

## Score history

- 2026-10-18: 57
- 2026-10-17: 57
- 2026-10-16: 57
- 2026-10-15: 56
- 2026-10-14: 55

## Common questions

### What is the Surface Contract: how platform APIs really behave MCP server?

Surface Contract: how platform APIs really behave is an MCP server listed in the public MCP registry as dev.workers.penny-mcamp.penny-surface-contract/surface-cont…. Evidence-cited machine-readable contracts for how agent platform APIs really behave. This page covers its hosted endpoint (https://penny-surface-contract.penny-mcamp.workers.dev/mcp).

### Is the Surface Contract: how platform APIs really behave MCP server safe to use?

Surface Contract: how platform APIs really behave scores 57 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 Surface Contract: how platform APIs really behave MCP server expose?

Surface Contract: how platform APIs really behave exposes 7 tools: list_surface_contracts, get_surface_contract, verify_surface, contribute_discrepancy, get_integration_recipe, and 2 more. Their descriptions and schemas cost roughly 1,024 tokens of context every time the server is loaded.

### Does the Surface Contract: how platform APIs really behave MCP server require authentication?

No. We connected to Surface Contract: how platform APIs really behave without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Surface Contract: how platform APIs really behave MCP server still maintained?

Surface Contract: how platform APIs really behave is still listed as active in the MCP registry. We last reached this channel on 18 October 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://penny-surface-contract.penny-mcamp.workers.dev/mcp
- Website: https://penny-surface-contract.penny-mcamp.workers.dev/
- Changelog RSS feed: https://verifymcp.io/servers/dev-workers-penny-mcamp-penny-surface-contract-surface-contract/penny-surface-contract.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-workers-penny-mcamp-penny-surface-contract-surface-contract/penny-surface-contract.json
- HTML version of this page: https://verifymcp.io/servers/dev-workers-penny-mcamp-penny-surface-contract-surface-contract/penny-surface-contract