ppsspp_session_list

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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description reinforces this with 'READ-ONLY.' Crucially, it discloses a subtle side effect beyond what annotations can express: idle sessions (>30 min) are auto-GC'd, and it preemptively clarifies this 'does not mutate the caller's state.' The description also names the exact data source (in-memory session dict) and the return shape, adding meaningful context without contradicting the annotations.

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 organized into labeled sections (PURPOSE, USAGE, BEHAVIOR, NOT, RETURNS) that make it highly scannable. Every sentence carries distinct information: scope, side effect, read-only behavior, sibling routing, the 'do I need this for an ID?' question, and return format. There is no redundancy or filler.

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 list tool with an output schema, the description is complete: purpose, side effects, alternatives, return shape, and even the most likely misuse (calling it just to resolve a session ID) are all covered. Nothing an agent needs to correctly select and invoke this tool is missing.

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?

With 0 parameters, the rubric baseline is 4, and the empty schema needs no compensation. The description explicitly states 'No parameters' and adds relevant selection context about session_id auto-resolution in sibling reader tools. It adds modest value beyond the schema but there is no parameter to elaborate on, so 4 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 PURPOSE section states a specific verb and resource: 'List all active PPSSPP sessions.' It goes further by explicitly distinguishing itself from siblings: 'NOT a per-session status probe,' naming ppsspp_smoke_test, ppsspp_get_pc, and ppsspp_query as the correct tools for those needs. An agent can select this tool 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 description gives explicit when-to-use and when-not-to-use guidance with named alternatives: use ppsspp_smoke_test for session health, ppsspp_get_pc/ppsspp_query for CPU/game state, and it warns that session_id-optional reader tools auto-resolve when one session is active, so 'you normally do NOT need to call this first just to obtain an ID.' Nothing is left to inference.

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