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

Annotations mark this as a non-read-only, idempotent write, but the description adds the substantive behavior: that it records rather than grants permission, that persist_identity writes a Cairn-only credential to private storage and why (identity across restarts), and that re-recording narrows scope. This is well beyond what the annotations convey.

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 critical ordering constraint ('never call it before the user answers') is front-loaded after the purpose statement, and every sentence carries distinct information. Slightly dense but no 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 consent/state-recording tool with no output schema and sparse annotations, the description supplies the essential behavioral context an agent needs to invoke it safely. The main gap is semantics for the max_per_visit parameter, which neither the schema nor description explains.

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 carry all parameter meaning. It explains mode ('this_action' stops auto-contrbutions) and persist_identity (stores credential in private storage), but leaves max_per_visit and the fixed scope constant unexplained. Partial compensation for the zero-coverage schema.

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?

States a specific verb and resource (record consent already granted) and, crucially, defines what it is NOT — 'This tool grants nothing.' This disambiguates the single most likely misuse (calling it to obtain consent) and cleanly separates it from the many sibling cairn tools.

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?

Explicit when/when-not: 'never call it before the user answers' sets a hard precondition, 'Re-record to change or narrow it' covers updates, and 'pass mode this_action to stop automatic contributions' gives the path to revoke. Nothing is left to inference.

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