About Probe V0
Probe is an experimental MCP server for agents that need to check explicit claims about public HTTPS endpoints against a bounded live observation. It stores timestamped evidence that can be reused when fresh enough or compared with past observations.
Key features
- 01Bounded HTTPS endpoint observations
- 02GET and HEAD requests
- 03Status, header, JSON Pointer, and body checks
- 04Timestamped, freshness-aware evidence
- 05Optional limited redirect following
Use cases
- 01Check an endpoint's current HTTP status
- 02Verify a specific response header or JSON value
- 03Compare a recent observation with historical evidence
MCP support
Probe exposes endpoint-observation capabilities to MCP clients. Its scope is limited to public HTTPS hostnames on port 443 and the supported assertion types.
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://probe-evidence.probe-lab.workers.dev/mcpclaude mcp add --transport http lexbritten-probe https://probe-evidence.probe-lab.workers.dev/mcp{"mcpServers":{"lexbritten-probe":{"type":"http","url":"https://probe-evidence.probe-lab.workers.dev/mcp"}}}Open in Cursor{"servers":{"lexbritten-probe":{"type":"http","url":"https://probe-evidence.probe-lab.workers.dev/mcp"}}}Open in VS Code{"mcpServers":{"lexbritten-probe":{"type":"http","url":"https://probe-evidence.probe-lab.workers.dev/mcp"}}}{"mcpServers":{"lexbritten-probe":{"serverUrl":"https://probe-evidence.probe-lab.workers.dev/mcp"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
Tools
2| Parameter | Type | Required | Description |
|---|---|---|---|
| url | string | Yes | Public HTTPS URL to observe. V0 forbids credentials, query strings, fragments, IP literals, private or local destinations, and non-443 ports. |
| method | enum | No | HTTP method to observe. Use HEAD only when response headers and status are sufficient.GET | HEAD |
| assertions | array | Yes | One to eight explicit assertions evaluated against the same HTTP response. |
| follow_redirects | boolean | No | Whether to follow up to three validated HTTPS redirects. Defaults to false. |
| freshness_seconds | integer | No | Maximum acceptable age of reusable matching evidence, in seconds. Public Probe V0 requires exactly 300. |
Details
From the project READMEProbe (experimental V0)
Probe lets AI agents empirically verify current claims about public HTTPS endpoints by making a bounded direct observation. This differs from web search or documentation, which report what sources say, and from model inference, which is not a live observation.
Probe persists timestamped, freshness-aware evidence so a sufficiently recent matching observation can be reused and historical observations can be compared.
V0 is intentionally narrow: public HTTPS hostname URLs on port 443; GET or HEAD; HTTP status, exact header, exact JSON Pointer value, or literal body-substring assertions. Public V0 requires freshness_seconds exactly 300.
Redirect following is opt-in with follow_redirects=true, limited to three 301/302/303/307/308 hops. Every destination must satisfy the same HTTPS, hostname, port, credential, query, fragment, and private/local safety restrictions. With the default false, Probe observes only the first response. Probe must not be used when the user's actual claim requires fetching an unsupported destination.
Probe does not provide a complete DNS-rebinding guarantee, uptime guarantee, SLA, authentication feature, or pricing commitment. It is experimental V0.
Comments
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