play_app_item

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

Annotations indicate readOnlyHint=false (mutation). Description says 'Play' confirming mutation but adds no details on behavior (e.g., whether it replaces current queue, error handling if player is off). Minimal incremental value over 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?

Single sentence with clear subject and object. No redundancy, but could be slightly more structured with if-then context. Highly concise.

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?

Given the tool has 3 required parameters, no output schema, and many sibling tools, the description is insufficient. It lacks information on what 'play' entails (start immediately? add to queue?), prerequisites (player must be on?), and error conditions.

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?

Schema coverage is 100% with descriptions for all parameters. The tool description adds 'by item ID', aligning with the itemId param, but does not provide new meaning beyond what's in the schema. Baseline score for high coverage.

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 verb 'Play', resource 'item from an online music app', and the key parameter 'item ID'. It effectively distinguishes from siblings like play_track (local) or play_favorite by specifying the source.

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?

No explicit guidance on when to use this tool vs alternatives like play_track or play_favorite. The description implies that the item ID comes from browse_app or search_app but does not state when to choose this over other play tools.

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