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

Annotations already disclose that this is a non-read-only, open-world, non-idempotent operation with destructiveHint=true. The description adds no behavioral context beyond listing the main fields; it does not explain side effects, permission requirements, or what the destructive hint means for an expense-creation tool.

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 efficient sentence, front-loading the core action and main fields. It is concise and contains no waste, though its brevity contributes to gaps elsewhere.

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 mutation tool with eight parameters, openWorldHint=true, destructiveHint=true, and no output schema, the description is thin. It does not address usage boundaries, required project enforcement beyond what the schema states, or behavioral implications of the mutation.

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 75%, and the schema itself documents key parameters including vendor_id, project_id, amount currency, and date default. The description names amount, date, vendor, and project but adds no semantics beyond what the schema already provides, and omits type, billable, and reason.

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 uses a specific verb and resource: 'Records an expense', with examples of what counts (receipt, purchase, fee). It clearly identifies the tool's purpose, though it does not explicitly differentiate it from siblings such as create_bill, create_purchase_order, or add_invoice_items.

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?

There is no guidance on when to use this tool versus alternatives like create_bill, create_purchase_order, or add_invoice_items, nor any prerequisites such as required project association. Usage must be inferred entirely from the tool name and schema.

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