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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the read-only nature is covered. The description goes beyond that by disclosing the underlying verification mechanism (Strype signature verified and re-read from api.server.com), the meaning of the two statuses, and that it is free. This is rich behavioral context for a read tool.

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 sentences, all relevant, with the core action and scope front-loaded. The 'Free.' fragment and the trustworhy explanation earn their place, though the description is slightly longer than strictly necessary. No redundancy 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 simple two-param read with annotations and no output schema, the description covers the essential invocation context, the meaning of the status values, and the follow-up action for PAID. It doesn't describe error handling for unknown quote_id or other possible statuses, which is a minor gap given the simplicity.

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 description coverage is 50%: account_key has a schema description, but quote_id does not. The description's 'for one quote' gives minimal context that quote_id identifies the quote, but it doesn't explain the format, that it's required, or how to obtain it. The description partially compensates for the missing quote_id schema coverage but doesn't fully close the gap.

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 first sentence, 'Reads the DFX payment ledger for one quote,' states a specific verb and resource, and the description clarifies the core question it answers: 'did my payment go through'. It does not explicitly name sibling tools like dfx_coverage or fund_dfx_account as differentiators, so it misses full sibling distinction, but the purpose 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?

The phrase 'It is the ONLY trustworthy answer to did my payment go through' gives an explicit when-to-use directive. It also excludes alternatives ('A browser redirect, a Stripe success page and a client's own belief are all not receipts') and provides action guidance based on statuses: 'AWAITING_PAYMENT means keep polling. PAID means ... repeat the paid call with authorize.'

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