Mithwire MCP

browser_set_file_input

Attach local files to a file input selector in a Chromium browser to automate file uploads during web testing.

Instructions

Attach local files to a file input selector.

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": {
      "session_id": "<session_id>",
      "selector": "<selector>",
      "file_paths": "<file_paths>"
    },
    "name": "browser_set_file_input"
  }
}

Input Schema

Name	Required	Description	Default
`selector`	Yes
`file_paths`	Yes
`session_id`	Yes
`wait_seconds`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.5.1Oct 18, 2026

TDQS

C2.8/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full behavioral burden. It mentions attaching local files but does not disclose side effects such as triggering change events, whether files are uploaded, required session context, selector constraints, or the role of wait_seconds.

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, front-loaded sentence with no wasted words. It is appropriately concise and easy to scan.

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?

Given the tool has four parameters, three of them required, and no annotation or schema descriptions, the definition is incomplete. The presence of an output schema covers return values, but critical invocation details such as the required session_id and wait_seconds behavior are absent.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must compensate but does so only vaguely. 'File input selector' hints at the selector parameter and 'local files' hints at file_paths, but session_id and wait_seconds are completely undocumented in both schema and description.

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 states a specific verb and resource: 'Attach local files to a file input selector.' This clearly distinguishes the action from siblings like browser_type or browser_click, though it does not explicitly name or contrast those alternatives.

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?

It gives no when-to-use guidance, prerequisites, or alternatives. The only implied context is that the tool is for attaching local files to a file input, but there is no explicit guidance on when this should be used instead of related browser actions.

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

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