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

Goes well beyond the annotations: describes the approval-inbox 202 flow, the verified-owner confirmation requirement, the sticky approval mode on recreation, cross-account inbox_not_found behavior, and the API-key limitation. These are exactly the edge cases an agent needs before calling a destructive tool.

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-loaded with the 'use this when' trigger, then effects, then the approval-mode caveat. Dense and information-rich, though several clauses about the confirm token and mail flow could be tightened without losing meaning.

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 destructive, open-world, non-idempotent-looking tool with no output schema, the description covers auth, side effects, the 202 approval path, error semantics, and return shape. An agent has everything needed to invoke correctly and interpret results.

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 baseline is 3. The description reiterates that inbox_id accepts id, username, or email, matching the schema but reinforcing it inline. Marginal added value, but accurate and consistent with the schema.

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?

Clear verb+resource (delete an inbox) with the secondary effect (frees slot on plan and workspace quota) stated up front. Distinguishes from siblings like cooper_delete_workspace and cooper_delete_thread by naming the specific resource and its side effects.

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?

States the trigger condition (inbox should be removed, freeing quota) and starts with 'Use this when,' which is explicit usage guidance. It doesn't name alternative tools or compare against cooper_update_inbox, but the condition is clear enough to select this tool.

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