fetch-chunk

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

Annotations already declare read-only, idempotent, non-destructive. The description adds valuable context: the 10-minute in-memory cache expiry, which is a critical behavioral constraint. It also clarifies that large responses may return only the first chunk plus a cacheKey, explaining the tool's place in the interaction flow. No contradiction with annotations.

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 that front-load the core purpose, then provide context and usage. Every word earns its place; no fluff or redundancy. Perfectly sized for the task.

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?

Given the tool's simplicity, the description fully covers what an agent needs: what it does, when to use it (with a cacheKey), how to use it (1-based chunkIndex), and the expiry constraint. No output schema exists, but the return value is implied to be the next chunk, which is acceptable for this tool.

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 baseline is 3. The description adds minimal extra meaning: it explains that cacheKey comes from the initial chunked response and that chunkIndex is 1-based with 2 as the next segment, which slightly reinforces the schema. However, it does not substantially go beyond the schema descriptions.

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 clearly states the tool's purpose with a specific verb ('Retrieve') and resource ('a cached chunk from a previously chunked response'). It distinguishes itself from sibling tools (ping, query, search, structured) by being the follow-up mechanism for fetching remaining chunks, which is explicit and unambiguous.

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 gives explicit usage context: use when a large query/search response returns a cacheKey and you need subsequent segments before the 10-minute expiry. It could be stronger by explicitly stating not to use without a cacheKey, but the scenario is clear and self-contained.

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