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Read-onlyIdempotent

Capture the current PPSSPP framebuffer as an image with metadata. Specifies render or output source, returns file path, and flags empty frames when no rendered scene is available.

Instructions

PURPOSE: Capture the framebuffer as an image (ImageContent) plus metadata.

USAGE: session_id optional when exactly one session is active; source='render' (default; empty frames auto-fall back to VRAM — colors unreliable there) or 'output' (CRASH-RISK, do not use); mutually exclusive with the deprecated mode param.

BEHAVIOR: READ-ONLY. An empty capture returns empty=true instead of an error — advance to a rendered scene and retry.

RETURNS: structuredContent metadata (mode/source/size_bytes/width/height/file_path/format/empty); the image itself arrives as an ImageContent block. The auto-saved PNG/JPG path is in file_path.

Input Schema

TableJSON Schema

Name	Required	Description
`mode`	No	DEPRECATED — use `source` instead. Legacy Win32 / VRAM fallback paths. 'auto' = three-tier fallback (wm_command → printwindow → vram). 'wm_command' / 'printwindow' / 'vram' = the specific strategy. Mutually exclusive with `source`.
`source`	No	Capture source (new, preferred). 'render' = with_stepping + gpu.buffer.renderColor (default when neither source nor mode is given). 'output' = gpu.buffer.screenshot (CRASH-RISK on some games). Mutually exclusive with `mode`.
`session_id`	No	Active session ID; omit to auto-resolve when exactly one session is active.

Output Schema

TableJSON Schema

Name	Required	Description
`mode`	Yes	Capture mode used. Echoes the caller's `mode` value ('auto'/'wm_command'/'printwindow'/'vram') on the deprecated path, or the `source` value ('render'/'output') on the new path.
`empty`	Yes	True when the capture produced no pixels (size_bytes=0 and no ImageContent). Agents can branch on this instead of parsing size_bytes heuristics — mirrors dump_texture's CAPTURE_EMPTY error.
`width`	Yes	Image width in pixels (0 if unknown).
`format`	Yes	Image format ('png' or 'jpeg').
`height`	Yes	Image height in pixels (0 if unknown).
`source`	Yes	The `source` parameter value when the new path was taken, or None when the deprecated `mode` path was used.
`file_path`	Yes	Path where image was saved.
`size_bytes`	Yes	Decoded image size in bytes.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 16, 2026

TDQS

A4.4/5.0

Behavior5/5

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

Beyond the readOnly/idempotent/destructive annotations, it discloses the render-to-VRAM auto-fallback, unreliable colors on VRAM, crash risk of 'output', and the empty=true instead of error behavior. These are precisely the behavioral traits that affect invocation and interpretation of results.

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?

Organized into PURPOSE, USAGE, BEHAVIOR, and RETURNS with each sentence carrying distinct information and no filler. The critical caveats are near the top and easy to scan.

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

Completeness5/5

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

With annotations covering safety and an output schema covering metadata, the description adds exactly what is needed: purpose, source selection rules, empty-capture semantics, and how the image is returned and where it is saved. No critical invocation detail is missing.

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

Parameters4/5

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

Schema coverage is 100%, so the schema already documents the parameters, but the description adds operationally important semantics: source default plus fallback behavior, the 'output' risk warning, mode deprecation and exclusivity, and the single-active-session condition for omitting session_id.

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?

States a specific verb, resource, and output: captures the framebuffer as an ImageContent plus metadata. The purpose is clear, but it does not explicitly distinguish itself from close siblings such as ppsspp_frame_snapshot or ppsspp_dump_texture.

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

Usage Guidelines4/5

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

Provides actionable usage conditions: session_id may be omitted when exactly one session is active, source='render' is the safe default, and source='output' is explicitly marked crash-risk and not to be used. It explains mutual exclusivity with the deprecated mode param, though it does not name alternative tools for when this tool should be avoided.

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