pix-mcp

by scarletfantasy

Overview Schema Source Related Servers Discussions Admin

Python

Local

pix_capture_app

Launch a D3D12 executable, capture GPU frames, and save them to diagnose rendering or performance issues.

Instructions

Launch a D3D12 executable, take GPU captures, and save them.

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": {
      "executable": "<executable>"
    },
    "name": "pix_capture_app"
  }
}

Input Schema

Name	Required	Description	Default
`winml`	No
`frames`	No
`remote`	No
`setenv`	No
`executable`	Yes
`capture_key`	No
`force11on12`	No
`output_file`	No
`command_line`	No
`capture_count`	No
`timeout_seconds`	No
`output_directory`	No
`working_directory`	No
`capture_from_start`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 9, 2026

TDQS

B3.1/5.0

Behavior3/5

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

Annotations already indicate this is not read-only and not idempotent. The description adds that launching an external executable and saving capture files are the side effects. It does not contradict the annotations, but it leaves out important behavioral details such as output locations, capture termination, timeouts, and effects on the launched process.

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

Conciseness4/5

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

The description is a single, front-loaded sentence with no filler. It is easy to parse and communicates the main action efficiently, though the brevity contributes to the lack of parameter and usage detail.

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 14 parameters, no schema descriptions, and side-effectful behavior, this description is not complete enough to support correct invocation beyond supplying the required executable. It does not explain preconditions, capture configuration, output defaults, or how this tool relates to sibling capture tools. The presence of an output schema helps with return shape but not with input semantics.

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?

With 0% schema description coverage and 14 parameters, the description needed to provide substantial parameter meaning, but it only hints at the executable and saving output. Most parameters, such as frames, capture_key, force11on12, remote, setenv, and output_directory, remain unexplained.

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 action ('Launch a D3D12 executable'), a clear resource, and outcomes ('take GPU captures, and save them'). This makes the core purpose understandable and helps distinguish it from sibling tools that target UWP apps or already-running processes, though it does not explicitly name 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 Guidelines3/5

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

The description implies this tool is for launching an executable and capturing GPU data, but it provides no explicit guidance on when to choose it over closely related sibling tools such as pix_capture_attached_process or pix_capture_uwp_app. The usage context is inferable but not directly stated.

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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