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

Annotations already cover safety (readOnlyHint, idempotentHint, destructiveHint=false), so the burden is lighter. The description adds example placeholder syntax and the 'Free' cost note, which is useful context, but it does not describe the return shape (list vs map) — reasonable since there is no output schema.

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?

A single front-loaded sentence with concrete examples and the downstream use case; 'Free.' is a small but informative trailing note. No waste.

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?

For a read-only, one-parameter tool with full schema coverage and safety annotations, the description supplies enough to call it correctly and understand its role. Only the return structure is left unstated, which is acceptable given no output schema.

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?

Schema coverage is 100% for the single file_id parameter, whose description already tells the agent where the ID comes from (files_upload/files_list). The description adds only that the target is a Word .docx template; this is a helpful hint but otherwise leaves parameter meaning to the schema.

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 identifies the exact resource (placeholders in a Word .docx template) and illustrates with concrete examples ({{ customer_name }}, {% for item in items %} loop), which lets an agent recognize template fields without opening the schema. The verb is implicit rather than stated, but the object and a downstream sibling (documents_fill_template) anchor it clearly.

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?

It explicitly ties use to a workflow: 'so you know what data documents_fill_template needs', which tells the agent to call this before filling. No when-not-to-use or state constraints are given, but the context is unmistakable.

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