gemini-fetch-chunk

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

With no annotations, the description carries the disclosure burden. It discloses two non-obvious behaviors: no model turn is consumed and cached data expires after 10 minutes. For a simple retrieval tool this is adequate, though failure behavior on cache expiry is not stated.

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 sentences with no filler; the verb and target are front-loaded and the behavioral caveats are packaged cleanly.

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 two-parameter cached retrieval tool, the essentials are present: what to pass, where the values come from, and that the cache is short-lived. Minor omissions are the exact return shape and expiry/error behavior, but an agent has enough to invoke it correctly.

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 covers both parameters 100%, so baseline is 3. The description adds provenance guidance—the cacheKey and chunkIndex come from the initial gemini-ask reply—which is more useful than either schema description alone.

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 precise action: retrieve one chunk of a chunked changeMode reply, scoped to data produced by gemini-ask, identified by cacheKey and chunkIndex. This clearly distinguishes it from siblings like gemini-ask or gemini-cancel.

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 implies the trigger: use after gemini-ask returns a chunked changeMode reply and supplies cacheKey/chunkIndex. It identifies this as a retrieval step rather than a model call and gives a 10-minute validity window, but it does not explicitly name alternatives or exclusions.

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