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

Annotations already declare readOnlyHint=false, openWorldHint=true and idempotentHint=false, so the mutation/external-call profile is partly covered. The description adds genuinely new behavioral context: it persists nothing and consumes the monthly AI allowance, which is a cost/quota trait no annotation conveys.

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 tight sentences, front-loaded with the transformation and followed by the operational caveats and downstream routing. No filler and every clause carries 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?

There is no output schema, and the description compensates by enumerating what the brief contains (sharper topic, tone, angles, key messages), while also covering cost and next-step usage. Nothing an agent needs to call it correctly is missing.

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 all four parameters (including the goal enum and platform list) are already documented in the schema. The description only alludes to 'the chosen platforms' and adds no format or syntax meaning beyond that, so the 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?

Specific verb ('Rewrite') plus resource ('raw topic or idea') plus the concrete output ('structured content brief: a sharper topic, suggested tone, content angles and key messages'). It also situates the tool in the workflow by naming generate_plan/generate_posts as downstream consumers, so an agent can distinguish it from those siblings.

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?

'Feed the result to generate_plan or generate_posts' gives clear context for when to call it (as an upstream step before generation) and the cost caution signals it should not be called gratuitously. However, it names no explicit alternative for the same job and states no when-not condition.

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