start_playback

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

The description gives no information about side effects, prerequisites, failure modes, or whether starting transport is idempotent. With no annotations to supplement, this leaves the agent unaware of important behavioral traits such as whether it initiates playback or what occurs if already playing.

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 a single, front-loaded sentence with no wasted words. It conveys the exact purpose efficiently.

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 action, the core purpose is stated, but the description lacks context about when to use it, what side effects it triggers, or any preconditions. The presence of an output schema covers return values, but the action's implications remain undisclosed, making it minimally sufficient yet incomplete.

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 tool has zero parameters, so the description has no obligation to explain parameter meaning. Baseline 4 is appropriate since there are no parameters to document.

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 action ('Start') and the target resource ('the session transport'), which is a specific, unambiguous operation. It naturally differentiates from its sibling tool 'stop_playback', which performs the opposite action.

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 guidance is provided on when to use this tool versus alternatives like stop_playback or get_transport. The description simply states what it does without any context about the intended workflow or selection criteria.

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