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

Annotations already cover readOnly/idempotent/destructive, but the description adds substantial context beyond them: derived fields (external_payment_ref, paid_before_confirmation, over_cap) that don't change the signed row, the pay_allowed gating logic, redaction behavior under public_view, that BotSupply doesn't move money, and that raw contact/confirm link/edit token are excluded. This is rich disclosure of non-obvious read semantics.

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 purpose, then dense but mostly load-bearing detail about status, pay_allowed, and redaction. It is a long single block with a few run-on sentences, but nearly every clause carries decision-relevant information.

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?

There is no output schema, so the description must describe the return shape, and it does so comprehensively (status values, derived flags, pay_allowed rule, redaction. Nothing an agent needs to call and interpret this tool is missing.

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?

With a single parameter at 100% schema coverage, the schema already fully documents receipt_id ('Public receipt id (rcpt_…)'). The description confirms the public nature of the id but adds no syntax or format beyond the schema, so the baseline 3 applies.

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 description opens with the specific verb+resource 'Read a public purchase receipt' and then enumerates the returned fields, so the agent knows exactly what this tool does. It does not explicitly differentiate itself from the sibling verify_receipt, which is the main thing keeping it below a 5.

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?

Provides clear operational context: 'Agents must poll get_receipt and pay only when pay_allowed is true' and 'Poll this to learn the click result.' This tells the agent when to call it, but it does not name or exclude alternatives (e.g., verify_receipt), so it stops short of full routing guidance.

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