update_expense

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

With no annotations provided, the description carries the full burden of behavioral disclosure. 'Update an existing card expense' implies a mutation operation, but the description doesn't disclose any behavioral traits: no mention of required permissions, whether the update is reversible, what happens to fields not specified, rate limits, or what the response looks like. For a mutation tool with zero annotation coverage, this is a significant gap in transparency.

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 that states the core purpose without any wasted words. It's appropriately sized for a tool with a clear name and good schema documentation. Every word earns its place, and the structure is front-loaded with the essential 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?

Given this is a mutation tool with no annotations and no output schema, the description is incomplete. It doesn't address critical context: what permissions are needed, what the response contains, whether the update is atomic, or how errors are handled. The agent has insufficient information to understand the full behavioral implications of invoking this tool.

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 schema description coverage is 100%, meaning all parameters are documented in the input schema. The description adds no additional parameter semantics beyond what's already in the schema (it doesn't explain parameter relationships, constraints, or examples). With complete schema coverage, the baseline score of 3 is appropriate - the description doesn't add value but doesn't need to compensate for schema gaps.

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 ('Update') and resource ('an existing card expense'), making the purpose immediately understandable. However, it doesn't differentiate this tool from potential sibling update tools (none are listed, but the agent might assume other update tools exist). The description is specific but lacks sibling differentiation.

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 provides no guidance on when to use this tool versus alternatives. There's no mention of prerequisites (like needing to identify an expense first), no comparison with other expense-related tools (like 'get_expense' or 'upload_receipt'), and no indication of when this update would be appropriate versus creating a new expense. The agent must infer usage context from tool names alone.

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