fetch_page

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

With no annotations, the description carries the full burden. It discloses that id uses an already-seen URL, summary mode de-noises mainText, and the output includes truncated and cached fields, which inform the agent about caching and truncation behavior. It does not cover failure modes or rate limits, but that is beyond typical selection criteria.

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 three tight sentences followed by an explicit output shape, with no filler. The core action is front-loaded, and every subsequent sentence adds information an agent needs for correct invocation. The output spec is lengthy but necessary since there is no output schema.

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?

Despite no annotations and no output schema, the description fully compensates: it explains purpose, parameter usage, behavioral nuances, and return value structure. The explicit output JSON gives agents a precise contract of what to expect, making the tool effectively self-contained. No critical selection or invocation information is missing.

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%, so the baseline is 3. The description adds meaning beyond the schema by clarifying that id looks up the already-seen URL and that summary extractMode 'saves tokens', directly addressing cost implications. The output block also connects maxLength to truncation and cached to caching behavior, which the schema alone does not.

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 opens with 'Fetch a page and return its content as structured Markdown', a precise verb-resource-output statement that leaves no doubt about the tool's function. It also differentiates from siblings by explaining the id comes from search/research, positioning fetch_page as the retrieval step after search.

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?

It explicitly explains when to pass 'url' versus the 'id' returned by search/research, including that id looks up an already-seen URL. It also gives a clear choice criterion for extractMode: summary saves tokens, full returns the complete page. It stops short of naming explicit alternatives or exclusions, but the workflow context is clear.

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