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

Annotations already indicate readOnlyHint=false, destructiveHint=false, and idempotentHint=true. The description adds valuable behavioral context: it resets generation_status to 'pending', queues regeneration based on feedback, and the new version waits for approval. It also clarifies the regenerate parameter's effect (immediate background queueing). This goes beyond what annotations alone provide.

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 sentences with no filler. The first sentence states the action and gives a concrete example; the second explains the downstream effect. Every word earns its place, and the most important information is front-loaded.

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 3-parameter tool with 100% schema coverage and no output schema, the description covers the action, the effect, and the regeneration workflow. It doesn't explain return values, but no output schema exists and the behavior is well-specified. The only minor gap is not explicitly stating that rejection is reversible or what happens to the old drafts, but the idempotentHint and destructiveHint annotations cover the safety profile.

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 the schema already documents all three parameters. The description adds context for 'reason' (used as regeneration feedback) and 'regenerate' (immediately queue a replacement draft), but these are also partially covered in the schema. The description doesn't add significant new meaning beyond the schema, so baseline 3 is appropriate.

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 ('Reject'), a specific resource ('current drafts on a campaign_contact'), and the key effect (resets generation_status to 'pending'). It also gives a concrete example of the feedback format. This clearly distinguishes it from approve_message, its main sibling, and from generate_campaign_message.

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 explains the workflow context: rejecting drafts with feedback triggers regeneration and the new version waits for approval. This implies when to use it (when drafts are unsatisfactory) and contrasts with approve_message. It doesn't explicitly name alternatives or state when not to use it, but the workflow context is clear enough.

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