Media Control

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

No annotations are provided, so the description carries the full burden. It does disclose a real behavioral trait — actions are dispatched to the *active* media session, and a supplied package_name is validated against that session and reported — but says nothing about failure behavior when no session is active or mismatched, or about prerequisites.

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 sentences, front-loaded with the primary capability, and the compact action list is tightly packed. No filler, though the enumerated verbs would be more useful if tied to the correct parameter name.

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?

An output schema exists, so return-shape explanation is not needed. However, with 4 undocumented parameters and an unresolved action/command ambiguity, the definition leaves an agent guessing about the exact call shape despite covering the high-level capability.

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 0%, so the description must compensate. It usefully defines the accepted action vocabulary and explains the origin of package_name (from get_media_sessions), but it never disambiguates the ambiguous 'action' vs 'command' parameters, and leaves 'device' unexplained.

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?

States a specific verb and resource ('Control playback in any app') and enumerates the exact supported actions, so an agent immediately knows it is the media-session control tool. It is clearly distinct from the volume_* siblings, though it does not name them explicitly.

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?

Usage is implied by 'control playback in any app without touching the screen', and it helpfully points at get_media_sessions as the source of package_name. It does not state when not to use it, nor how it relates to siblings like volume_up/mute.

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