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

With no annotations, the description carries the full burden and does: auto-creates missing users, replay returns the original transaction with idempotent_replay: true and mints/sends no second webhook, on-chain mint status is reported, and a 1 CRD fee is charged even on rejection except 429. It also discloses that errors carry a request_id for support escalation.

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?

Four dense sentences, front-loaded with the core action and side effect, then idempotency, then on-chain/cost behavior, then error handling. No restated name or 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 14-parameter mutation tool with no annotations and no output schema, the description covers the critical behaviors: creation side effects, dedupe semantics, billing cost, and the shape of response/error fields. An agent could call this correctly and safely without reading anything else.

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 the baseline is 3; the description goes further by tying idempotency_key to a concrete retry policy and by naming the replay flag and mint behavior the parameter triggers. It does not explain x402_payment or project_id redundancy, leaving some multi-param interactions to 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?

States a specific verb and resource (issue/add credits to a user) plus a non-obvious side effect (creates the user on email-first lookup). Against siblings like deduct_credits and refund_credits the direction of the credit movement is unambiguous.

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 explicit when-to guidance for idempotency_key ("anything an agent might retry") and warns that omitting it re-issues on every call. It stops short of routing the agent to alternatives such as deduct_credits for negative movements or explaining the x402_payment retry path, which only appears in the schema.

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