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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds that recovery does not trigger execution or a new payment, which is useful, but it does not disclose additional behavioral details such as failure modes or conditions for a quote being valid.

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?

The description is a single front-loaded sentence with no filler. Every phrase carries meaning: 'paid', 'with its payment identifier and original signed quote', and 'without execution or another payment' all add necessary constraints.

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 read-only retrieval tool with two required string parameters and no output schema, the description covers the key invocation decision: the outcome is already paid and should be recovered without re-executing. It could add more about return value shape or preconditions like obtaining the signed quote, but the description is sufficiently complete for correct invocation.

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 0%, so the description carries the burden of explaining the parameters. It does name both required inputs ('payment identifier' and 'original signed quote'), mapping to payment_identifier and quote, and adds the nuance that the quote must be signed. However, it does not describe formats, provenance, or how these values are obtained.

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 uses a specific verb ('Recover') and a specific resource ('a paid public outcome'), and states the exact inputs ('payment identifier and original signed quote'). It also distinguishes the operation from execution or another payment, which differentiates it from siblings like xguard_execute and xguard_quote.

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 'without execution or another payment' conveys when to use this tool: only to retrieve an already-paid outcome, not to initiate or pay for execution. It does not explicitly name alternative sibling tools, but the contextual constraint is clear enough for routing.

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