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Paperboy

Paperboy

Official
by sudostash

fill_form

DestructiveIdempotent

Populate PDF form fields with validated values, optionally flattening the result into a static document.

Instructions

Fill in form fields: values maps each field's full name to its value.

Text and choice fields take text; checkboxes take true/false; radio groups take one of their options, or "Off" to clear (see list_form_fields). Multi-select list boxes take a single value. Every value is checked first and nothing is written if any is invalid. If unrenderable_fields is not empty, the form's font can't draw those values: they are stored, and most viewers redraw them correctly. flatten=true makes the result static (no longer editable), which needs the owner password if the PDF forbids changing comments or changing it. Signed PDFs are refused because filling would break the signature.

Any password argument can be "ask": the user then types it on a local page, so it never passes through the chat.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "input_path": "<input_path>",
      "values": "<values>"
    },
    "name": "fill_form"
  }
}

Input Schema

NameRequiredDescriptionDefault
valuesYes
flattenNo
passwordNo
overwriteNo
input_pathYes
output_pathNo

Output Schema

NameRequiredDescriptionDefault
filledYes
outputYes
flattenedYes
xfa_removedYes
password_protectedYes
unrenderable_fieldsYes
usage_rights_removedYes
user_password_changedYes
permissions_restrictedYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Addedv0.1.1

TDQS

A4.2/5.0
Behavior5/5

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

Beyond the annotations, the description discloses important behavior: all values are validated before anything is written, unrenderable fields are stored but may redraw correctly, flattening makes the PDF static and may require an owner password, and signed PDFs are refused. It also explains that a password argument can be 'ask' so the password never passes through chat.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core values mapping, then moves through field-type rules, validation behavior, edge cases, and password handling. Every sentence contributes operational detail, and there is no redundant wording.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex form-filling tool with an output schema and no parameter descriptions, the description covers the most important behavior and failure modes well. It is not fully complete because output_path and overwrite are not explained, which matters for a destructive operation that may write or replace files.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden of parameter meaning. It thoroughly explains the complex values parameter, flatten, and the password 'ask' option, but it does not explain input_path, output_path, or overwrite, leaving three of six parameters without added semantic detail.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource, 'Fill in form fields', and immediately explains how values map to fields. It also distinguishes part of its behavior from list_form_fields by pointing to that sibling for radio-group options and clearing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives useful behavioral constraints such as refusing signed PDFs and writing nothing if any value is invalid, but it does not explicitly say when to choose fill_form over other tools. The reference to list_form_fields is helpful for radio options, yet it is not a general routing guideline.

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