search_messages

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description mentions it searches 'cached messages' (implying it doesn't hit live sources), but doesn't clarify whether the search is scoped to a single account, what happens with the limit default, or how results are ordered. 'Cached' is a meaningful caveat but under-specified.

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, zero waste. The description states the core behavior and the one optional parameter that needs clarification. Efficiently front-loaded with the purpose in the first sentence.

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 search tool with 4 params, an output schema, and sibling tools, the description is somewhat thin. It names the search semantics and the days constraint but doesn't cover limit/account parameters, and with zero schema coverage and no annotations there are gaps. The cached-messages framing hints at scope limitations but doesn't fully elaborate.

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 description coverage is 0%, so the description must compensate for all 4 parameters. The description covers 'days' explicitly and 'query' implicitly (it's the search term), but says nothing about 'limit' or 'account'. The description adds some value for days but leaves half the parameters undocumented.

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 states a specific verb+resource ('Case-insensitive substring search across cached messages'), which is clear about what the tool does. However, it doesn't differentiate from siblings like recent_messages or mentions, both of which also deal with message retrieval/search, so the purpose isn't fully distinct.

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 explains the optional days parameter restricting to last N days, which gives some context on when to use it. However, there's no explicit guidance on when to use this vs. recent_messages, unread_messages, or mentions, and the sibling names create ambiguity about which search approach to choose.

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