extract_fields

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

No annotations are provided, so the description carries the full disclosure burden. It does disclose failure modes (corrupt PDF, bad schema), the exact return contract ({ok: True/False}), and the non-empty properties requirement. However, it omits the side-effect profile (e.g., read-only disk access) and edge behaviors such as empty extraction results, so disclosure is solid but not exhaustive.

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?

Purpose is front-loaded in a single line, followed by a clean Args/Returns structure that is scannable. Slightly padded by trailing ellipses and the '...' after the failure list, but overall efficient with no 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 no annotations and no output schema, the description covers the return format, failure modes, and semantic details of both parameters—enough to call the tool correctly. Gaps are minor: no sibling-routing guidance and the meaning of the returned 'text_length' field is undefined.

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 0%, so the description must supply meaning. It adds substantial context: schema may be a JSON Schema object, a built-in name like 'invoice', or a .json file path, and must have a non-empty 'properties'; pdf_path is explained as a path to the PDF. This goes well beyond the bare type declarations.

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 opening sentence states a specific verb (extract), a resource (structured fields), and a source/method (unstructured PDF using regex/heuristics). This clearly distinguishes extraction behavior from list_supported_document_types, though it doesn't explicitly name the differentiation from validate_against_schema.

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?

No guidance on when to choose this tool versus its siblings. It doesn't mention when validate_against_schema or list_supported_document_types would be the better pick, and states no preconditions or exclusions beyond the inline schema-constraint note in Args. The agent must infer usage context.

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