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

The description adds the 'time.approve' permission requirement, which is not present in the annotations and provides useful auth context. However, it does not disclose postconditions such as status change, reversibility, or side effects. The annotations already indicate this is a non-read-only but non-destructive operation, so the mutation is known but its behavioral details are left to inference.

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 sentence with no redundancy. The action is front-loaded ('Approve an expense') and the permission requirement follows directly. Every word earns its place, making it an appropriately sized and well-structured definition for such a simple tool.

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, no-output-schema mutation tool, the description is mostly sufficient: it states what the tool does and what permission is needed. It does not explain the consequences of approval or how to find the expense_id, but these can be reasonably inferred from sibling tools like timelog_get_expenses. Minor gaps remain but they are not critical 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%, and the description does not mention expense_id at all. The parameter name is self-explanatory in context, but the description fails to compensate for the missing schema documentation by explaining what the ID refers to or how to obtain it. This leaves the agent to infer parameter semantics from the name alone.

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 clearly states the action and resource: 'Approve an expense.' It distinguishes from the sibling timelog_approve_time by naming 'expense', but it doesn't elaborate on what approval entails beyond the title. The description is essentially a full-sentence version of the title, so it is clear but not rich.

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 description gives no guidance on when to use this tool versus alternatives like timelog_approve_time or timelog_update_expense. It only mentions the permission requirement, which is a prerequisite but not a usage condition. No context, exclusions, or alternative routing is provided.

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