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

With no annotations, the description must disclose behavioral traits on its own. The verb 'Fetch' implies a read-only operation, but it does not mention error behavior, authentication requirements, or what happens if the receipt is not found. Minimal behavioral detail beyond the operational verb.

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, concise sentence that front-loads the action and resource. No filler or redundant wording; it earns its place without waste.

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 low complexity (one param, no output schema, no annotations), the description is minimally viable: it states the action and target. However, it leaves gaps such as return format or possible error states, which would be valuable to know. It is adequate but not 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?

The input schema has one parameter (receipt_id) with 0% description coverage. The description's phrase 'by id' aligns with receipt_id but adds little semantic value beyond what the schema states—it does not clarify format, constraints, or relationship to the resource.

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 'Fetch' with a clear resource 'signed receipt envelope' and identifies how to target it ('by id'). This distinguishes it from sibling tools like check_approval or verify_receipt, which imply different actions.

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?

No guidance is provided on when to use this tool vs. alternatives. The description simply states what the tool does without any contextual or exclusionary information about sibling tools.

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