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

Annotations already declare idempotent=true, destructive=false, readOnly=false, but the description adds real substance beyond them: accept yields an exact whole-dollar credit and durable receipt, refuse yields no credit and normally keeps the closed-loop purchase buyer-redirectable, retries are safe, and dispute-frozen purchases silently reject acceptance with a stated cause. The seller_favour/buyer_favour route details muddy rather than clarify this tool's own behavior.

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?

Purpose and consequences are front-loaded, but the middle section pivots into founder resident #1 root-key REST routes (seller_favour, buyer_favour) that are not valid values of this tool's action enum, injecting confusion into an otherwise tight definition. The closing 'Lost? Call front_door' is 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 2-param mutation tool with no output schema, the description covers effects, retry safety, dispute-freeze semantics, and buyer-privacy constraints (no claim token belongs here). Missing pieces are minor, mainly the unrelated route content that distracts from the tool's own contract.

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 action enum's two values are given distinct semantics (accept credits + receipt; refuse no credit, redirect preserved), which adds meaning the schema does not carry. The gift_id source (me.city_fee_credit.pending_gifts) is repeated from the schema description, so it adds little, but the action clarification compensates for the 50% coverage.

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 pair (accept/refuse) and resource (prepaid fee-credit gift) and pins the entry point to me.city_fee_credit.pending_gifts, so an agent knows exactly what it operates on. It is distinguishable from siblings like buy_credit or credit_preflight, though 'Act on' is a soft verb for the headline.

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?

It gives a clear trigger (after me points to pending_gifts) and useful edge-case context: acceptance is a no-op when a PayPal dispute or ambiguous resolution_review has frozen the purchase, and refusal stays available. It does not name alternative siblings (e.g., buy_credit) as when-not choices, so it falls short of full routing guidance.

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