PCSX2 MCP

by snowyegret23

Overview Schema Source Related Servers Discussions Admin

Python

Local

write_memory

Write hex bytes to a specified guest memory address to modify emulated game data directly.

Instructions

Overwrite guest memory with hex bytes.

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": {
      "address": "<address>",
      "data_hex": "<data_hex>"
    },
    "name": "write_memory"
  }
}

Input Schema

Name	Required	Default
`target`	No	ee
`address`	Yes
`data_hex`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 27, 2026

TDQS

C2.5/5.0

Behavior2/5

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

No annotations provided. The description only states 'overwrite guest memory' but does not disclose side effects, prerequisites (e.g., paused VM), or behavioral traits like alignment or caching. Minimal transparency beyond the obvious destructive nature.

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

Conciseness3/5

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

One sentence, very concise, but arguably too terse. It loses important details for the sake of brevity. Could be more structured with separate statements for each parameter.

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

Completeness1/5

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

Given the complexity of a memory write operation and no output schema, the description is severely incomplete. It does not mention return values, error conditions, or required system state (e.g., emulation paused).

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 description must compensate. 'Hex bytes' clarifies data_hex, but address and target are unexplained. The description adds little meaning beyond the schema field names.

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?

Description clearly states it overwrites guest memory with hex bytes, providing specific verb and resource. However, it does not explicitly differentiate from sibling like overwrite_memory_from_file, which also overwrites memory but from a file, so sibling distinction is implicit.

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?

No guidance on when to use this tool vs alternatives (e.g., write_register, overwrite_memory_from_file). The description is purely functional and lacks context for selection.

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