estimate_payment_cost

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

With no annotations, description carries full burden. It fully discloses read-only nature, that nothing is sent on-chain, and details the cost components: base fee, priority fee, and ATA rent-exemption for first-time recipients. No contradictions.

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?

Two sentences packed with essential information: purpose, usage context, behavioral traits. No redundant words, front-loaded with the main action. Every sentence earns its place.

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?

Given the tool's simplicity (1 param, full schema, no output schema, no annotations), the description covers everything needed: purpose, usage timing, what costs are estimated, and safety guarantee. Complete.

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?

Only one parameter with 100% schema coverage; the schema already describes it as 'JSON-serialized payment_request blob.' The description does not add additional parameter-level detail beyond the schema, so baseline 3 is appropriate.

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?

Description clearly states 'Estimate the SOL cost of submitting the transaction that would pay a given payment_request.' It identifies the specific verb (estimate) and resource (SOL cost for payment_request), and distinguishes from sibling send_payment by noting it's a read-only estimation.

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?

Explicitly says 'Useful before send_payment on a USDC invoice' and 'Read-only: does not send anything on-chain.' This gives clear when-to-use guidance, though it doesn't explicitly list when not to use or alternatives beyond the implied pre-send context.

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