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

Annotations only cover the safety profile (readOnly=false, destructive=false, openWorld=false); the description adds decisive behavior beyond that: the tool returns a curl_command already shell-escaped, the OAuth user is auto-recorded as uploader, and the command must be run exactly as returned without re-quoting.

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?

Dense but front-loaded, leading with the mechanism and then required/optional/forbidden fields before the return-value warning. Every clause carries information, though the density makes it slightly heavy for a single-param tool.

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?

Covers the non-obvious contract end to end: metadata-only submission, identity handling, the curl_command return, and the run-as-is constraint. With an output schema present, return details are legitimately handled there, so nothing an agent needs is missing.

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?

Despite 0% top-level schema coverage, the description fully specifies semantics: filename is a local path with no control characters, name is optional and only when it should differ from the basename, description is optional, and uploaded_by must be omitted. This is more than the schema conveys on its own.

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?

States a specific verb and resource ('Upload a PDF attachment') and clarifies the unusual mechanism ('without sending file bytes through this tool'). It distinguishes itself from generate-api-key explicitly, though it never names its true sibling upload-attachment_multipart_form_data, leaving that distinction to inference.

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?

Gives explicit when-to-use and when-not-to-use: required vs optional fields, 'Do not send uploaded_by', 'Do not base64-encode the PDF into this tool', and 'do not use generate-api-key for uploads'. The agent has unambiguous routing rules.

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