fill_form

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

Beyond the annotations, the description discloses key behavioral constraints: the input PDF is never changed, `out_path` must be inside an allowed root, must not already exist unless `overwrite` is true, and symlinks are refused. It also explains partial success behavior—only `set` fields are written, `unknown` fields are named, and nothing is written when no field is set.

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 front-loaded with the core action, then adds behavioral constraints and a compact Args section. Every sentence earns its place by covering a distinct rule or parameter, with no filler.

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 four-parameter mutation tool that writes files and has an output schema, the description covers the essential preconditions, partial-success behavior, and safety constraints. Nothing an agent needs in order to call it correctly appears to be 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?

Although the schema has 0% description coverage, the description fully documents all four parameters. It explains `path` and `out_path` as absolute paths, maps `values` to field names with the exact value types expected (string, list of strings for multi-select), and clarifies `overwrite` semantics.

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 opens with a specific verb and resource: 'Fill the form fields of a local PDF and write the result to a new file.' It clearly distinguishes this from sibling extraction tools and from list_form_fields by naming the latter as the source of field names.

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 gives a clear usage context by tying `values` to field names from `list_form_fields`, implying the need to discover fields first. It does not explicitly name alternatives or when-not-to-use cases, which keeps it from a 5.

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