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

Annotations only indicate readOnlyHint=false, which signals mutability. The description adds crucial behavioral context: the tool revokes the API key for already-approved pairings, works both pending and after approval, and has a specific time window. This goes well beyond what annotations provide, making the side effects and constraints explicit.

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?

The description is concise, consisting of three sentences that each carry essential information. It front-loads the primary purpose, then adds timing and alternative guidance, and finally suggests the follow-up action, all without redundancy or unnecessary filler.

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?

Despite having no output schema, the description fully covers the operational scope: what the tool does, when it is usable, what happens after use (API key stops working), and what to do next. The sibling tools and parameter schema provide enough context to invoke correctly without additional clarification.

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?

The input schema already provides complete descriptions for both parameters (claim_token and pairing_code) with 100% coverage. The description does not add additional parameter-level detail, but the schema fully documents them, so a baseline score of 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 opens with a specific verb and resource: 'Abort a pairing you started with register_agent.' It clearly distinguishes the tool from the sibling revoke_self by explicitly naming the alternative, ensuring an agent understands which operation this tool performs.

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 provides explicit usage guidance, including when the tool is valid ('Available until the pairing expires, and for 15 minutes after you pick up the API key') and when to use an alternative ('later than that, use revoke_self'). It also instructs to call register_agent again afterward, giving complete context for proper usage.

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