Agent Evidence API

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It explicitly discloses the return shape ('Returns only {status, service, version}'), confirms it 'exposes no secrets or infrastructure detail', and notes it is free to call. This is meaningful behavioral context beyond the schema, though it stops short of describing error behavior or rate limits.

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?

The description is two sentences with no filler. It front-loads the main purpose, then adds cost and return details. Every clause earns its place.

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 simple, parameterless health check, the description fully covers purpose, usage conditions, return format, and safety (no secrets). Nothing an agent needs to call it correctly is missing, especially given the minimal schema and no output schema.

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?

The tool has zero parameters and schema coverage is 100%, giving a baseline of 4. The description reinforces this by stating it 'takes no arguments', providing no additional parameter semantics needed.

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?

The description states a specific action ('Check that the Agent Evidence API MCP server is reachable') and the resource (the server) plus what it reports (service version). It is clearly distinguishable from the sibling 'research_evidence' which implies evidence lookup, not health checking.

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?

The description says it is 'Free to call, takes no arguments or payment', implying it can be used anytime without cost or prerequisites, but it does not explicitly state when to prefer this over the sibling tool or mention any exclusions. Usage is implied rather than spelled out.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full behavioral disclosure burden. It reveals non-obvious traits: fresh web evidence is retrieved per request unless served from a bounded cache, each source reports its actual retrieval time, and every excerpt is cited evidence tied to its source URL. These constraints go well beyond a simple 'fetch sources' statement.

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?

The description is front-loaded: it states the core purpose and deliverable first, then lists use cases, return fields, freshness behavior, and citation guarantees. Each sentence contributes a distinct useful fact with no filler or redundancy.

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?

Without an output schema, the description compensates well by listing return elements: source URLs, retrieval timestamps, evidence excerpts, publisher/document metadata, and an explicit verdict. However, it does not restate at the description level that version 0.1.0 requires at least one candidate URL, even though the schema's urls property mentions this, so an agent might attempt to call with only the required 'question' field.

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?

The input schema already describes all 5 parameters with 100% coverage, including enum values, bounds, and meaning. The tool description adds little parameter-specific detail beyond what the schema provides, so the baseline score of 3 is appropriate.

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?

The opening sentence uses a specific verb ('Fetch public web sources') and names the deliverable ('structured, cited web evidence') for a question or claim. It goes on to enumerate exact use cases and return fields, so an agent can tell it apart from the unrelated sibling tool 'health'.

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?

The description explicitly states when to use the tool: 'Use this for source verification, claim verification, evidence extraction, and source-grounded research, or to compare sources.' It provides clear context but does not state exclusions or compare with an alternative evidence-gathering tool, though the only sibling is unrelated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.