list_form_fields

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds semantics the annotations cannot: the enumerated field types, 0-based page indexing, null when a field has no page widget, and that an empty list means no AcroForm exists — all behaviorally useful. It omits failure modes (encrypted or malformed PDFs), which keeps it off a 5.

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 purpose is front-loaded in the first line, then the return-shape details follow in a compact block. The field-by-field prose partly duplicates an existing output schema, but each clause still carries meaning (0-based pages, fully qualified names), so there is little true 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 one-parameter read tool with annotations and an output schema, this covers what an agent needs: what it returns, what empty means, and the absolute-path requirement. The remaining gap is routing — no statement of when to prefer this over get_metadata or the extract_* siblings.

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% — the single `path` property has no description at all — so the description must compensate, and it does by specifying 'the PDF's absolute path on this machine', which tells the agent a relative path is insufficient. That is the one constraint an agent could plausibly get wrong, so the gap is adequately filled.

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 the resource precisely — the interactive form fields of a local PDF — and ties it to the sibling fill_form by noting the name is what fill_form takes. It is phrased as a noun fragment rather than a verb ('list'), and it does not explicitly distinguish itself from get_metadata or the extract_* siblings, but the resource is unambiguous.

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?

Usage is only implied: the mention that `name` is the fully qualified name fill_form consumes hints at the inspect-then-fill workflow. There is no explicit guidance on when to choose this over get_metadata or extract_* tools, and no stated prerequisites such as the file needing to exist or be unencrypted.

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