get_performance_metrics

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is known. The description adds the prerequisite of run_interactive and clarifies optional filtering, which adds useful behavioral context beyond the annotations. It does not describe return format, but that is not a major gap for this simple read tool.

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?

The description is three short sentences that are all essential: purpose, optional filtering, and prerequisite. It is front-loaded with the main action and contains no filler or redundancy.

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 single-optional-parameter read tool with good annotations, the description covers the core aspects: what it does, the optional filter, and the prerequisite. It doesn't define return values or error behavior, but given the simplicity of the tool and the annotations, it is sufficiently complete.

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 schema fully documents the 'metrics' parameter (optional array of strings, default all). The description repeats this with 'Optionally filter to specific metrics,' adding no additional meaning. Since schema description coverage is 100%, baseline 3 is appropriate.

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?

The description clearly states the tool retrieves performance metrics (FPS, draw calls, memory, node count) from a running project, with an optional filter. This is a specific verb+resource+scope that distinguishes it from sibling tools like get_debug_output or get_scene_insights.

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 description explicitly mentions 'Requires run_interactive,' which is a clear prerequisite and context for when to use this tool. It implies use when the project is running and the user needs performance metrics, but it does not explicitly name alternatives or provide exclusions, hence not a 5.

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