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

Annotations already cover the safety profile with readOnlyHint, idempotentHint, and destructiveHint=false. The description adds useful behavioral context: the session must already be mounted, the refresh happens in place, and get_session does not open library stories or drive playback. The output schema covers return-shape details.

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, each earning its place: the polling scope, the refresh action, and the sibling routing. It is front-loaded with the core purpose 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 one-parameter, read-only, idempotent polling tool with an output schema, the description covers purpose, usage context, parameter semantics, and alternative tools. Nothing needed to invoke it correctly 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?

Schema description coverage is 0%, so the description must compensate for the single sessionId parameter. It does by referring to existingSessionId and an already-mounted PlayableSession, making clear that sessionId must reference an existing active session rather than a story or arbitrary string.

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 states a specific action: it refreshes one PlayableSession in place for an already-mounted OffStereo card. It also distinguishes itself from siblings by assigning story-opening to make_playable(existingSessionId) and playback/contextual follow-ups to steer_session.

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 frames get_session as application polling for an already-mounted card, giving an explicit when-to-use context. It names make_playable and steer_session as the tools for opening and steering, respectively, which clearly routes the agent away from get_session for those cases.

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