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

Annotations already declare destructiveHint=true and idempotentHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: only incoming pending requests qualify, where to source the id, and a required user-confirmation step before the destructive call.

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?

A single front-loaded sentence carrying the action, the constraint, the id source, and the confirmation rule, with no 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?

For a one-parameter destructive mutation, the definition covers the action, the eligibility constraint, the parameter source, the confirmation obligation, and relies on annotations for the safety/idempotency profile. No output schema is needed for a simple acknowledge-style action.

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?

With schema coverage at 100% and a single required parameter, the schema fully documents request_id and even names its source. The description restates the same provenance, adding no syntax or format detail beyond structured fields, 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?

States a specific verb (decline) plus resource (incoming pending friend request) and constrains scope to INCOMING requests, which cleanly separates it from friend_request_accept, friend_request_send, and friend_request_resend. An agent can identify the correct tool 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?

Gives clear preconditions: the request must be an incoming pending one, and the id should come from friend_requests_pending. It also adds an operational guideline ('Confirm with the user before calling'). It does not explicitly name friend_request_accept as the alternate action, but the routing is unambiguous from context.

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