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

No annotations are provided, so the description carries the burden. It discloses that a signed receipt is returned, which is useful behavioral context. However, it doesn't explain what 'signed' means, whether the operation is idempotent, or what happens if the ref is invalid. The receipt return is a positive disclosure, but more depth would be better.

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 with no waste. The required/optional parameter summary is front-loaded. It's appropriately concise, though it could add a bit more context without becoming bloated.

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 tool with 3 parameters, 0% schema coverage, no annotations, and no output schema, the description is too thin. It doesn't explain what 'for' and 'name' are for, what a 'signed receipt' contains, or any error conditions. An agent would likely need to guess or call the tool to learn more.

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 must compensate. It mentions 'ref required; for and name optional' but doesn't explain what 'for' and 'name' mean semantically. The description adds minimal value beyond the schema's required field list. It doesn't clarify the format or purpose of each parameter.

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 states a specific verb and resource: 'Records a reference being cited.' This clearly distinguishes it from siblings like canon_search (searching) and receipt_verify (verifying receipts). It could be slightly more specific about what 'reference' means, but the core purpose is clear.

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 on when to use this tool versus alternatives. It doesn't mention that canon_search is for finding references or that receipt_verify is for checking receipts. The description implies usage (when you want to record a citation) but provides no exclusions or alternatives.

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