get_current_screenRetrieve the last captured emulator frame as a PNG without advancing the game, enabling screen inspection; fails if no game is loaded.
Returns the last captured emulator frame as a PNG image without advancing the game. Fails if no game is loaded.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavior: the return type (PNG image), that game state is not advanced, and the failure condition when no game is loaded. It stops short of describing caching or image dimensions, but the key state and error semantics are disclosed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences with zero filler; the return value is front-loaded and the constraint and failure mode follow. Every clause carries information an agent needs.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-parameter, read-only tool with full annotation coverage, the description supplies everything remaining: return format (PNG), state behavior (no advance), and the error case (no game loaded). No output schema is needed given the return type is stated.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. No parameter text is needed or missing.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Names a specific verb+resource ('Returns the last captured emulator frame') and immediately disambiguates from the sibling skip_frames by stating it works 'without advancing the game.' An agent can pick this over skip_frames without opening any schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'without advancing the game' gives clear context for when this is the right choice versus frame-advancing siblings, but it never names an alternative tool explicitly or states when not to use it. Clear context, no exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.