expensify_update_expense_rule

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

Annotations show destructiveHint=true and readOnlyHint=false. The description adds critical context not in annotations: 'WRITES to Expensify. Dry-run is currently ON — this will preview only.' This clearly discloses the mutation and temporary preview mode, exceeding what annotations alone provide.

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 concise sentences: the first states the action and key identifier, the second adds essential behavioral context about write and dry-run. No filler, all sentences earn their place.

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?

The description covers the action and dry-run behavior but omits details about the response format, error conditions, or permissions. For a mutation tool with no output schema, more context would be helpful, but annotations partially compensate.

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 ~50% description coverage (some parameters lack descriptions). The tool description does not add any parameter-level details beyond the schema, so its value is marginal. With moderate schema coverage, a baseline score of 3 is appropriate.

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 'Modify an existing expense rule by its ruleID', specifying the action (modify) and the resource (expense rule), differentiating from similar tools like expensify_create_expense_rule. The additional note about dry-run further clarifies the current behavior.

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 indicates it is a write operation with dry-run enabled, but does not provide explicit guidance on when to use this tool versus alternatives (e.g., create vs update), or prerequisites like policyID or employeeEmail requirements.

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