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

Annotations already declare read-only, idempotent and closed-world, and the description adds substantially more: no credits or user data consumed, the entire bounded catalog returns in one response, registration does not guarantee live collection, and calls must be sequential on the public endpoint. It further explains that HTTP 429 signals admission denial rather than an empty result and prescribes honoring Retry-After with jittered backoff — exactly the operational context an agent needs.

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 resource and returned fields, then follows with the ID-reuse rule and the rate-limit protocol. Every sentence carries operational information, but the rate-limiting tail is dense enough that it slightly dilutes the core catalog purpose.

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?

With no output schema, the description still enumerates the returned fields and states that the catalog is complete and bounded in a single response, so the agent knows the shape and extent of the result. Combined with the rate-limit and ID-reuse guidance, nothing material is missing for correct invocation.

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?

The tool takes zero parameters, so there is nothing to disambiguate and the description correctly states 'No arguments.' Baseline for a parameterless tool applies; the extra note about using the returned ID elsewhere is useful but belongs to usage rather than parameter semantics.

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 (List) plus the exact resource and returned fields: configured public Threat Intel source ID, name, format, surface and source URL from the pinned collector registry. It also implicitly distinguishes itself from siblings by naming ti_latest.source as the consumer of these IDs.

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?

Explicitly says to use the exact returned ID in ti_latest.source and that guessed aliases are rejected, which routes the agent correctly. It also states 'No arguments' so the agent knows no query shaping is possible, though it does not explicitly say when to prefer ti_get or ti_classes over this catalog.

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