veilbrowser

veil_fill

Use accessibility element references to click and fill form fields with human-typed cadence for stealth browsing.

Instructions

Click a field by ref and type text into it (human cadence).

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": {
      "ref": "<ref>",
      "text": "<text>"
    },
    "name": "veil_fill"
  }
}

Input Schema

Name	Required	Description	Default
`ref`	Yes
`text`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.5.0Jul 29, 2026

TDQS

C2.7/5.0

Behavior2/5

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

No annotations are provided, so the description bears full responsibility. 'Human cadence' suggests simulated typing delays, but it does not disclose whether the field is cleared first, how errors are handled, or if it waits for the field to be ready. The behavior is under-specified.

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 a single, well-structured sentence of 13 words. It front-loads the main action ('Click a field by ref and type text into it') and added the qualifier 'human cadence' efficiently. No unnecessary words.

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

Completeness2/5

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

For a tool with 2 required parameters, no output schema, and no annotations, the description is too minimal. It lacks information about return values, error cases, and the meaning of 'ref'. Compared to sibling tools, it does not fully explain when this combination is beneficial.

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

Parameters1/5

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

The input schema has 0% description coverage, and the tool description adds no parameter-specific details beyond the property names 'ref' and 'text'. It does not explain what 'ref' is (e.g., CSS selector, XPath, index) or the expected format of 'text'. The description fails to compensate for the lack of schema descriptions.

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

Purpose4/5

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

The description clearly states the tool clicks a field and types text, effectively distinguishing it from sibling tools like veil_click (just click) and veil_type (type into focused element). However, the term 'human cadence' is somewhat vague but still conveys basic behavior.

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

Usage Guidelines2/5

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

The description provides no explicit guidance on when to use this tool versus alternatives. It implies use for filling form fields but does not contrast with using veil_click then veil_type separately. No when-not-to-use or prerequisite information.

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