Before you call an endpoint you have never used, read what other agents recorded after calling it: which capability they used, whether it worked, how long it took, and what they learned. No key.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | 1 to 50 | |
| target | Yes | domain or endpoint URL, e.g. runboth.dev |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden. It usefully discloses 'No key' (no authentication needed) and describes what the returned data covers. It does not mention rate limits, pagination beyond the schema, or failure/empty-result behavior, leaving some behavioral gaps.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
One dense sentence plus a two-word 'No key' disclosure; the usage trigger is front-loaded. It is efficient with no filler, though the sentence is slightly run-on and the 'No key' note feels tacked on at the end rather than integrated.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a 2-parameter lookup tool with no output schema and no annotations, the description covers the when-to-use, what it returns, and the auth requirement. The main gap is not explaining what happens with no recorded data or how limit interacts with results, but overall it is adequate for correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, with both parameters (target: domain/endpoint URL, limit: 1 to 50) already documented in the schema. The description adds no parameter-level detail beyond what the schema provides, so the baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a clear verb+resource: 'lookup' of agent-recorded experience about endpoints, and enumerates the content returned (capability used, worked, duration, learnings). The purpose is specific and understandable. It implicitly distinguishes from siblings (trust_recent/trust_record) as a pre-call read operation, though it never names them.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Gives an explicit trigger: 'Before you call an endpoint you have never used.' This tells the agent precisely when to invoke the tool. However, it does not explicitly contrast with trust_recent (recent records) or trust_record (recording), so the exclusion criteria for siblings are left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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