Find Message Recipients

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

Annotations already declare readOnlyHint=true, so the bar is lower, yet the description adds real behavior: only individuals are returned, non-staff appear as Student_<hash> pseudonyms under anonymization, and name searches then match staff only. These are non-obvious result-shaping traits an agent would otherwise get wrong; only pagination/limit behavior is left unstated.

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 tight sentences: what it returns first, the workflow use second, the anonymization caveat last. No repetition of title or schema content, and every sentence carries decision-relevant information.

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?

With a full schema, an output schema, and readOnlyHint annotations, the description covers the parts that matter (scope of results, anonymization effects, intended follow-up tool). It does not mention result ordering or that limit caps matches at 50 beyond the schema, a minor 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 coverage is 100%, so the baseline is 3, but the description adds meaning the schema only partially conveys: the anonymization caveat on search ('matches only course staff') clarifies a subtle query-time behavior beyond the field's own text, and the individuals-only note constrains interpretation of results.

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 and resource ('Find people you can message in a course') plus the concrete output (Canvas user IDs) and a scope constraint ('Only individual people are returned'). It does not explicitly contrast with look-alike siblings such as list_users or get_group_members, so an agent must infer the distinction, which keeps it just below a 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?

Gives a concrete usage moment ('look up your instructor's or TA's user ID before send_message'), naming the downstream tool explicitly. It lacks an explicit when-not condition or named alternative lookup tool, but the intended workflow is clear.

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