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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real context beyond that: the exact set of terminal and non-terminal states, the fact that a human wallet signature is attached once a decision is made, and that the call incurs no cost. Error/not-found behavior for a bad ID is not covered.

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 short sentences: the core purpose and return shape first, then the cost note. No filler, no restating of the title, and every clause carries 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?

For a one-parameter read-only tool with annotations covering safety, this is nearly complete. Because there is no output schema, the description usefully describes the return (state values plus signature), which is the main burden it needed to carry; only invalid-ID and freshness/timing behavior are unaddressed.

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 100% and the single approval_id parameter is documented there as an 'apr_... ID', so the baseline is 3. The description adds no syntax, format, or lookup semantics beyond what the schema already states.

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 resource (an approval request) and the exact information returned: its status, enumerated as pending/approved/denied/expired/cancelled, plus the wallet signature. That enumeration clearly separates it from approval_wait (which presumably blocks) and approval_list, though neither sibling is named explicitly.

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 when-to-use guidance is given. An agent must infer that this is a non-blocking point-in-time check, and nothing in the text explains when to prefer it over approval_wait or approval_list. Only the trailing 'Free.' hints at a selection factor (cost).

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