update_expense_attachment

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

Beyond the destructiveHint annotation, the description discloses that the 'data' parameter must be Base64 encoded and that user confirmation is required. This adds useful behavioral context. However, it does not mention side effects like replacing or deleting the previous attachment, which would be expected for an update operation.

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 extremely concise: a single line with a warning emoji, the main action, data format requirement, and a user confirmation note. Every sentence adds value. There is no repetition of schema annotations or other unnecessary details.

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 is adequate for a simple update tool: it states the purpose and a key constraint (Base64). However, it lacks context about the effect on existing attachments (e.g., replacement or deletion), potential requirements (e.g., existing expense must exist), and does not guide the agent on handling errors or outcomes. The presence of an output schema is noted but not described, which is acceptable per rules.

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 description only adds semantic meaning for the 'data' parameter by stating it must be in Base64 format. For 'expense_id' and 'filename', no additional meaning is provided beyond the schema's property names and types. Given that schema description coverage is 0%, the description partially compensates but is not comprehensive.

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: 'Actualiza el adjunto de un gasto' (updates the attachment of an expense), specifying the verb and resource. It distinguishes from siblings like get_expense_attachment, delete_expense_attachment, and create_expense by focusing on updating an existing attachment.

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 includes 'Confirmar con usuario' (confirm with user), implying this tool should be used with caution and explicit user consent, which provides some usage context. However, it does not explicitly state when to use this tool over alternatives like delete_expense_attachment plus create_expense, nor does it list prerequisites or forbidden scenarios.

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