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

Annotations give readOnlyHint=false, openWorldHint=true, destructiveHint=false, so the safety profile is covered. The description adds real behavior beyond them: the 'once' framing and the returned snapshot_id imply the page state is captured and persisted for later use, which explains the non-read-only hint. It does not disclose failure behavior for unreachable URLs, rate limits, or what the token requirement means in practice.

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?

Two short sentences, zero filler, and the core behavior is front-loaded before the return-value/next-step information. 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?

There is no output schema, so the description carries the return-value burden and does name the two outputs (paragraphs, snapshot_id). But it leaves offset/pagination, the auth token flow, and error behavior unexplained for a 4-parameter open-world fetch tool, so it is only partially complete.

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 75% (url, find, token documented; offset undocumented). The description explains the purpose of the returned paragraphs ('to copy an exact quote from'), which connects loosely to the find parameter, but it adds no syntax or semantics for find, offset, or token. With coverage this high, the schema does the heavy lifting and baseline 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?

States a concrete action (server fetches/reads a source page) on a concrete resource (URL) and names the sibling it feeds (add_evidence via snapshot_id). An agent can distinguish it from add_evidence without opening the schema. It stops short of a crisp one-line 'what it is' framing, but the verb+resource+downstream link are all present.

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 phrase 'snapshot_id for add_evidence' implies the intended workflow (snapshot first, then add_evidence), and 'read a source page once' implies a fetch-before-quote pattern. However, there are no explicit when-to-use/when-not conditions, no statement about whether it must precede add_evidence, and no mention of alternatives.

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