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

Annotations already cover read-only, non-destructive, and open-world behavior, so the description does not need to repeat those. It adds context about the suggestions being from a connected channel while drafting a post, but does not disclose details like result limits, pagination, or response structure. This is fine given the annotations, but the description adds only modest behavioral context.

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 description is three sentences long, all of which contribute value: the core action, the use case, and the specific trigger for use. It is front-loaded with the main purpose and avoids verbose detail. Minor redundancy exists between 'on a channel' and 'from a connected channel', but it is not problematic.

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?

This is a simple read-only tool with two required parameters fully described in the schema and no output schema. The description adds enough context about when and why to use it. It does not describe the return format, but for a suggestions lookup this is not a critical omission given the simplicity.

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%, with both 'query' and 'channelId' already described. The description does not add additional meaning beyond the schema, which keeps this at the baseline for high schema coverage.

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 ('Search') and a specific resource ('@mention suggestions on a channel'), making the tool's purpose clear. It also distinguishes itself from the get_/list_/view_ sibling tools by focusing on mention suggestions rather than general content retrieval. The wording is not tautological and adds useful context about finding users/pages.

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 explicitly says when to use this tool: 'Use this when you need @mention suggestions from a connected channel while drafting a post.' It does not mention alternative tools or provide exclusions, but the use case is clear enough for an agent to select it appropriately.

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