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

Annotations already declare readOnly/idempotent/non-destructive/non-open-world, so safety is covered. The description adds genuinely useful behavior beyond that: a privacy constraint (private notes excluded unless the agent enabled its memory vault) and a data-safety guarantee (returns resource links, never credentials). These are non-obvious scoping rules an agent could not derive from the 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?

Three short sentences, each earning its place, with the core purpose front-loaded and the two behavioral caveats tight and non-redundant. No filler or restatement of the tool name.

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?

An output schema exists, so return-value structure needn't be explained, and annotations cover the safety profile; the description fills the remaining gaps (privacy scoping, credential safety, mention-composer context). The only shortfall is the undocumented query parameter, which leaves a small completeness gap.

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 50%: the connection parameter is richly documented in the schema, while query has no description. The description implies query is free-text search input ('Search ... for the composer') but adds no syntax, format, or length guidance, so it neither compensates for the undocumented query param nor extends the well-documented connection param. Baseline 3.

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 (Search) and enumerates the resource scope (rooms, channels, agents, shared pages) that this tool covers, which naturally distinguishes it from a generic messages_search. The phrase 'for the composer' pins down the context (mention autocomplete) so an agent can identify the use case without opening the schema. It stops short of naming the sibling it replaces, so it's 4 rather than 5.

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?

'for the composer' implies the tool is used for mention/autocomplete lookup rather than general message search, giving an implied usage context. However, no explicit when-to-use vs when-not-to-use guidance and no sibling alternative (e.g., messages_search) is named, leaving the agent to infer the boundary.

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