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

Annotations already flag destructiveHint=true, readOnlyHint=false, and idempotentHint=true. The description adds genuinely useful context beyond them: the write changes only Adako-side settings ('nothing changes on an ad platform') and is free/not task-counted, which materially changes how an agent should reason about it. It stops short of explaining reversibility or what happens to the stored reason.

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-loads the WRITE banner and lead sentence, and each section earns its place. Minor redundancy: cost is stated twice ('Cost: free' in the header and a trailing 'Free.').

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 mutation tool with no output schema, the description covers the effect, the trigger, the cost model, and the side-effect scope, with annotations carrying the safety profile. The only real hole is that it never points at where a valid proposal_id comes from.

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 50%; raw_data and idempotency_key are self-documented. The description adds real meaning for reason ('store the user's reason... it improves future proposals'), but proposal_id — the required parameter — is undocumented in both schema and description, leaving its source (presumably list_pending_proposals) to inference.

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 (reject) applied to a specific resource (pending proposal) plus the concrete effect: 'so it will never execute.' An agent can immediately distinguish it from the sibling approve_proposal without opening either 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 an explicit trigger: 'Use when: the user says no to a proposed change.' The natural alternative (approve_proposal) is not named, so the routing is clear but not exhaustive.

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