fetch_page

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

With no annotations, the description carries the burden and does well: it discloses that rendering happens through a real Firefox (so JS pages work), that `query` switches output from page-head to topic-relevant excerpts, and that an SSRF guard blocks internal addresses — a real operational constraint. It omits rate limits, timeouts, and failure behavior, so not a full 5.

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?

Front-loaded with the outcome, then WHEN / NOT WHEN / parameter note / constraint, each on its own labelled line. No filler sentences; every clause carries decision-relevant information.

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 4-param fetch tool with an output schema (so return shape needn't be described), the definition covers purpose, selection criteria, key param behavior, and one hard constraint. The remaining gap — max_chars and the format enum — is the only thing an agent might need to infer.

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 0%, so the description must compensate. It meaningfully explains two of four params (url target, query semantics, and format via 'markdown или чистый текст'), which is above the baseline. However, `max_chars` is never mentioned and format's allowed values are only implied, leaving half the surface undocumented.

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 specific verb+resource (fetch the text of a page) and adds a discriminating implementation detail ('настоящим Firefox', real Firefox, i.e., JS-capable rendering). It distinguishes itself from web_search and, by implication, from link-oriented siblings. An agent can tell exactly what this tool returns: markdown or plain text.

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?

Explicit WHEN/НЕ КОГДА structure: use it to read a concrete URL including JS-heavy pages; do NOT use it when what you need is topic-relevant links, in which case route to web_search. The named alternative makes the routing decision unambiguous.

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