extract_evidence

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful behavioral detail: each passage includes a context window, relevance score, and character offset for verifiable citations. It does not discuss failure modes or rate limits, but the annotations lower that burden.

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?

Three sentences with no filler: the first states the action, the second describes the output, and the third gives usage guidance. Information is front-loaded and every sentence 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?

An output schema exists, so return values need not be fully described, and annotations cover safety. The description covers purpose, output behavior, and usage. It could be more complete by naming sibling alternatives or elaborating on max_passages, but those are minor gaps.

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 description coverage is 67%, with url and question already described and max_passages constrained by min/max/default. The description adds the notion of relevance and passage context but does not clarify max_passages behavior beyond what the schema provides. This is a baseline 3 situation.

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 ('Fetch a URL and extract the passages most relevant to a specific question') and a clear resource. It differentiates itself from sibling tools like fetch_url and search_web by emphasizing evidence extraction with context windows and verifiable citation offsets.

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 final sentence gives an explicit trigger condition: 'Use this when you want to drill into a specific source for evidence on a narrow claim.' This clearly indicates when the tool is appropriate, though it does not explicitly name alternatives or state when not to use it.

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