Search mentions

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

Annotations already carry readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful context beyond these: that it searches a 'connected channel' (external platform data, reinforcing openWorldHint) and serves the drafting workflow. No contradictions with 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?

The core function is front-loaded in the first sentence, which is ideal. The remaining two sentences provide workflow context, though 'Useful for finding users/pages to mention in posts' and 'Use this when you need @mention suggestions from a connected channel while drafting a post' are partially redundant and could be merged. Still, nothing is wasted.

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 simple tool (2 required parameters, no nested objects, no enums) with annotations covering the safety profile and a fully documented schema, the description is adequately complete. It clarifies the use case and scope. Minor omissions like result format and rate limits are acceptable given the tool's simplicity and read-only nature.

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 100%, so both parameters are already fully documented in the schema ('Search query for the mention lookup' and 'The channel ID to search mentions on'). The description echoes 'on a channel' but adds no format, syntax, or behavioral detail beyond what the schema provides, so baseline 3 is appropriate.

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 opens with a specific verb+resource+scope construction: 'Search for @mention suggestions on a channel.' This precisely identifies what the tool does and naturally distinguishes it from all siblings, none of which perform mention lookup. The '@mention' detail makes the resource unambiguous.

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 gives explicit when-to-use guidance: 'Use this when you need @mention suggestions from a connected channel while drafting a post.' This anchors the tool to a concrete workflow. It stops short of a 5 because it names no alternatives or explicit when-not-to-use conditions, though no competing sibling exists.

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