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

The description discloses key behaviors beyond annotations: it creates a new job_id with parent_job_id linking to the source, and instructs to use the new job_id for viewing the result. While annotations declare non-read-only and non-destructive, the description adds valuable context about the job lifecycle. It does not mention potential side effects like whether the old password remains valid, but the provided behavioral details are substantive.

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 concise (three sentences) and well-structured: the first sentence states the purpose, the second explains the job_id behavior and follow-up action, and the third gives an explicit exclusion. Every sentence earns its place without redundancy.

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?

With 5 required parameters, an output schema, and a sibling set_password, the description covers the essential workflow: it explains the new job_id creation, how to view the result, and when not to use the tool. It omits details like error handling or whether the operation requires the old user password, but the presence of the output schema and schema descriptions reduces the burden. Overall, it is nearly complete for its complexity.

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 has 100% description coverage for all 5 required parameters, so the baseline is 3. The description does not add new parameter-level details beyond the schema, but it does clarify the operational sequence (e.g., old_password is the current user password) implicitly through context. No additional compensation is needed.

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 function: 'Change the password of an already-protected PDF file.' It specifies the target (PDF) and differentiates from sibling set_password by explicitly mentioning 'already-protected' and instructing to use set_password for unprotected PDFs.

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?

Provides explicit usage guidance: tells the user to call view_pdf after completion to display the result, and explicitly warns not to use this tool on unprotected PDFs, directing to set_password instead. This is a clear when-to-use and when-not-to-use with an alternative named.

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