submit_payment

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

Annotations only cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true); the description adds real value beyond that by disclosing that the call blocks until confirmation and that idempotency_key guarantees no double payment on retry. It stops short of describing failure/timeout behavior or how long the confirmation wait can be.

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?

Three short sentences, front-loaded with the action and followed by the two most important behavioral guarantees. No filler or repetition of the name or annotations.

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 states the return value ('the signed receipt') and covers idempotency and blocking behavior. It is complete enough to invoke correctly, though error/failure handling for a broadcast transaction is unaddressed.

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 67% — quote and transaction are documented inline, but idempotency_key is not. The description compensates by explaining that retrying with the same idempotency_key never pays twice, giving that parameter concrete semantics the schema lacks.

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 ('broadcast') and resource ('a transaction the payer already signed'), plus the post-conditions: waits for confirmation and returns the signed receipt. This cleanly separates it from siblings like quote_payment and build_payment without needing to open 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?

'Only broadcasts; never signs or pays payment transactions' establishes a clear when-not boundary and implicitly routes signing to build_payment. However, it never names the alternative tool explicitly, so the agent must infer the routing rather than being told.

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