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

Annotations already declare readOnly, idempotent and non-destructive, but the description adds material behavior the annotations cannot: a 60-minute handle TTL, the handle_not_found error contract, and the cost trade-off between paging and re-filtering. That is real operational context beyond the structured fields.

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 core action and the three view modes, then usage guidance, then expiry semantics. Dense but every clause carries information; the opening sentence runs long, which is the only cost.

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 an output schema existing, the description still conveys enough for correct invocation: what each view yields, how to page, when to prefer run_op, and what an expired handle produces. Nothing an agent needs 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 75% and limit/offset/handle are already documented in the schema, so the baseline is 3. The description goes further by explaining what each enum value of 'view' actually returns and how next_offset drives paging, adding meaning the schema's bare enum does not carry.

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 verb+resource ('Read a stored result (handle) without running anything') and immediately enumerates the three view modes, which lets an agent distinguish it from run_op, read_page and run_pipeline. The scope ('without running anything') is exactly the boundary an agent needs.

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?

Gives an explicit trigger ('when a result came back as a preview and you need more of it') and names the alternative path with the condition that selects it: check est_tokens first, and prefer narrowing with run_op (find, select, filter, fit) over paging. It also covers the failure case (expired/unknown id) and the remedy.

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