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

Annotations already convey readOnlyHint=false, and the description adds valuable behavioral detail: output is a pointer { id, presignedUrl }, the URL expires in ~15 minutes, runs can be inspected via get_edit_run, and llmContext guidance should be followed. The target-vs-source warning also surfaces a common misuse.

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 dense but every sentence earns its place: purpose, value sources, target/source caveat, documentation prerequisite, output format, expiry, and follow-up inspection. It is front-loaded with the core purpose and avoids 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 complex mutation tool with 7 parameters, the description covers the full workflow: what inputs to pass, how they are derived, what the output looks like, how to monitor it, and how to handle expiration. The output schema exists, and environment/workspace constraints are already in the schema, so nothing critical 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?

Schema coverage is 100%, so the baseline is 3, and the description adds meaningful semantics beyond the schema: file must be the target form rather than the source, schema should come from detect_form_fields with extend_edit keys, and instructions are free-form prose with a concrete example. This justifies a score above baseline.

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: fill form fields in a PDF and return the edited file. It also distinguishes itself from parse/extract siblings by explicitly requiring the TARGET form, not the source document, which removes ambiguity about its role in the pipeline.

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 workflow guidance: parse or extract the source first, use a schema from detect_form_fields, call get_documentation before hand-authoring a schema, inspect runs with get_edit_run, and re-fetch expired output with get_file. This tells the agent when to use this tool and which sibling tools support it.

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