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

Annotations already declare readOnlyHint/idempotentHint/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely new behavioral context by enumerating what each returned rating contains, including the distinction that user-scoped results carry extra job/context fields. It omits any mention of volume, limits, or pagination.

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?

Front-loads what the tool returns and how it differs from inline averages, then moves to parameter routing and return fields. Dense but every sentence carries information, since the last two sentences substitute for a missing output schema.

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 no output schema, the description does the work of documenting the return payload field by field, and it states the parameter exclusivity rule. Remaining gaps are minor: no pagination/result-count behavior and no note on what happens with an unknown username.

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 schema baseline is 3, but the description adds the 'exactly one of username or job_id is required' rule that the empty required list in the schema does not express, plus a plain-language gloss of direction. It stops short of adding format details (UUID, exact-case matching) that the schema already supplies.

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+resource ('Read individual ratings') and immediately differentiates the tool from the aggregate view an agent might otherwise use ('not just the average that job results inline'). The distinction is actionable without opening any schema.

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?

Explicitly maps each parameter to a usage mode: username for received ratings, username+direction 'given' for left ratings, job_id for a single job's pair, and it states the 'exactly one' constraint. It covers how to use the tool thoroughly but never names an alternative tool or a when-not-to-use condition.

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