Execute Payin (Deposit)

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

Annotations already declare the mutation/retry profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the description builds on rather than repeats them: it explains that idempotency_key exists to 'safely retry without double-charging' and that the client must pay the returned PIX to complete the deposit. Auth requirements and quote-expiry behavior are not covered, but the financial-consequence context is a genuine addition.

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-loaded with the verb and resource, then the prerequisite, return values, and the final clarifying sentence about who pays the PIX — all useful. The Args block partially duplicates schema descriptions, which is the only wasted surface, but the whole definition stays short.

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?

With no output schema, the description correctly enumerates the return fields (payin_id, status, and the PIX payload components including pix_copiacola, pix_qrcode_base64, expires_at), and it names the required upstream call. For a money-moving mutation it could add more on quote expiry or duplicate-execution errors, but an agent has enough to invoke it correctly.

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 baseline is 3; the description earns a bump by adding meaning the schema lacks — the idempotency key is framed in terms of double-charge protection, not just as an 'optional idempotency key'. The payin_quote_id semantics are only restated from the schema, so the gain is modest.

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 ('Execute a PIX deposit') and ties it to a prerequisite artifact ('a previously created payin quote'), which cleanly separates it from ashar_create_payin_quote (prepares the quote) and ashar_get_payin (reads status). An agent can place it in the payin lifecycle without opening another 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?

The prerequisite is explicit: it must be called with a quote id from ashar_create_payin_quote, which tells the agent when this tool is applicable and which sibling precedes it. It does not state failure modes (expired quote, already-executed quote) or when to re-execute vs. re-fetch, so it stops short of full when/when-not guidance.

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