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

Annotations already declare readOnly, idempotent, non-destructive, so safety needs no restating. The description does add one genuinely useful behavioral fact: matching spans replies as well as the original message, widening recall beyond the top-level body. It says nothing about result ordering, whether matches are ranked or truncated, or how the limit is applied.

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, front-loaded with the core action and followed by the one behavioral nuance that matters. The 'already diagnosed in a reply' clause earns its place by concretely illustrating the recall behavior rather than padding.

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?

There is no output schema, so the description must carry all expectations about results, and it does not say what a match returns, whether ordering is by relevance or recency, or how limit and status shape the page. Adequate for the matching semantics, thin for anything an agent needs to interpret the response.

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 only 50%: query and projectId are documented in the schema, while limit and status carry no description anywhere. The description does not mention any parameter, so the two undocumented ones (including the status enum's effect on results) get no compensating explanation.

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 ('Find') and resource ('items') plus the matching scope: text appearing anywhere in the item's thread, including replies. That is enough to separate it from list_items or get_item, though it never names a sibling to sharpen the distinction from find_similar or find_by_source.

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 phrase 'whose thread mentions some text' implies keyword search, which lets an agent infer it is not the tool for a known item id (get_item) or an exact source lookup (find_by_source). But there is no explicit when-to-use statement, no exclusion, and no guidance on when find_similar is the better choice.

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