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

The readOnlyHint annotation already declares this a safe read, so the bar is lower. The description contributes the upstream endpoint (GET /v3/users/{userID}), which aids traceability, but says nothing about behavior on an unknown id (error vs empty) or the shape of the result.

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 short sentences, front-loaded with the operation, zero filler. The endpoint reference is compact and appended rather than buried.

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 one-parameter read tool with annotations covering safety and no output schema, this is nearly sufficient. The only gap is unspecified error behavior for a nonexistent id, which is a minor omission rather than a blocker.

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 a single required userId parameter, so the schema fully documents the input. The description's 'by their id' adds no format or syntax detail beyond the schema — baseline 3 applies.

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 ('Get a single user by their id'), and the singular scope distinguishes it from the sibling squadcast_list_users without naming it. It could have explicitly named the list sibling to make routing unambiguous, but the purpose itself is clear.

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 phrase 'by their id' weakly implies the agent must already hold a user id, but there is no explicit when-to-use guidance, no prerequisites, and no mention of the sibling squadcast_list_users as the alternative for discovery. This is essentially no guidance.

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