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ppsspp_health

Read-onlyIdempotent

Check if the PPSSPP MCP server is running and ready by probing liveness counters without contacting the emulator. Use this read-only health check before session-dependent tools to verify availability and avoid failures.

Instructions

PURPOSE: Probe MCP server liveness and readiness without contacting PPSSPP. Use this before any session-dependent tool to verify the server is up.

USAGE: No parameters.

BEHAVIOR: READ-ONLY. Reads in-memory server counters (uptime, registered tool count, active session count). Does not contact PPSSPP and does not modify any state.

RETURNS: Dict with status ('ok'/'degraded'), version, python_version, pydantic_version, uptime_s, tool_count, session_count.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description
`status`	Yes	Server status: 'ok' when all subsystems healthy; 'degraded' when sessions.json is inaccessible/corrupted but server is otherwise functional.
`version`	Yes	MCP server version.
`uptime_s`	Yes	Server uptime in seconds.
`tool_count`	Yes	Number of registered MCP tools.
`session_count`	Yes	Number of active sessions.
`session_error`	Yes	When status='degraded', describes the sessions.json issue (e.g. 'FileNotFoundError: ...' or 'JSONDecodeError: ...'). None when sessions.json is healthy.
`python_version`	Yes	Python interpreter version.
`pydantic_version`	Yes	Pydantic version.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 16, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description's added value is explaining exactly what it reads ('in-memory server counters') and that it 'does not contact PPSSPP and does not modify any state.' This goes beyond the annotations and gives the agent a concrete picture of the tool's behavior.

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 organized into clear labeled sections (PURPOSE, USAGE, BEHAVIOR, RETURNS) and every sentence carries key information. It is front-loaded with the purpose and usage, and contains no filler.

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?

For a simple health-check tool with zero parameters and an output schema, the description fully covers purpose, usage, behavior, and return format. It even includes the possible status values and specific return fields. Nothing an agent needs to invoke it correctly 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?

The tool has zero parameters and schema coverage is 100% (trivially). The description explicitly states 'No parameters,' which is all that is needed. The baseline of 4 for zero parameters applies.

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?

Description states a specific verb ('probe'), resource ('MCP server liveness and readiness'), and explicitly differentiates from siblings by saying 'without contacting PPSSPP' and 'Use this before any session-dependent tool'. An agent can clearly distinguish this health-check tool from the many PPSSPP interaction tools.

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?

It gives an explicit when-to-use instruction: 'Use this before any session-dependent tool to verify the server is up.' It also implies not to use it for PPSSPP state checks via 'without contacting PPSSPP', but does not name specific alternative tools or provide a when-not-to-use list, so it falls short of the full 5.

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