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

Annotations indicate destructiveHint=true, which the description does not contradict. The description adds file size and extension restrictions but does not explain other behavioral traits (e.g., whether duplicate filenames are handled, if the file replaces an existing one).

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?

Three concise sentences, front-loaded with purpose, followed by constraints. No fluff, every sentence adds necessary 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?

The description covers purpose and constraints adequately but does not mention the return value or success/failure behavior. Given no output schema, the agent might benefit from knowing what is returned (e.g., the file ID or confirmation).

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?

With 100% schema coverage, baseline is 3. The description adds value beyond the schema by specifying the 25 MB size limit and listing allowed extensions, which are not in the schema fields. It reinforces the base64 encoding requirement.

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 tool's purpose: 'Attach a document to a case' with specific examples like invoice copy, contract, etc. It uses a specific verb-resource pair and is distinct from sibling tools (e.g., list_case_files).

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 explicit constraints (max 25 MB, allowed extensions, base64 encoding) that guide usage. It does not explicitly mention when not to use or name alternatives, but the context makes it clear this is the sole upload tool.

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