play_podcast_episode

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

With no annotations to rely on, the description carries full behavioral burden and succeeds: it discloses the AX-discovery mechanism, explains that the play pill position varies per page and is never hardcoded, describes the ~15s TTML cache polling, and states the return values. This is exemplary transparency.

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 sentences, front-loaded with the main action. Every sentence adds value: what it does, how it does it, and what it returns. The parenthetical about AX-discovery is slightly verbose but serves a purpose (justifying the non-hardcoded approach). No waste.

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 tool with no parameters, no output schema, and no annotations, the description covers all necessary aspects: the action, the mechanism (including potential timeout), the return values, and the prerequisite. It also links to the downstream tool (get_podcast_transcript), making it contextually complete within its ecosystem.

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 0 parameters, so per the rubric the baseline is 4. The description doesn't add parameter-specific semantics (none exist), but it adds contextual meaning by explaining what the tool does and its outputs, which is sufficient.

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 tool's function: 'Plays the currently open episode page in Apple Podcasts' using a specific mechanism (AX-discovers the play pill). It distinguishes this from sibling tools like open_podcast_episode (which opens the page) and pause_podcast_episode (which pauses), making the purpose unambiguous.

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 an explicit prerequisite: 'Requires open_podcast_episode to have been called first.' It also explains the relationship to get_podcast_transcript by returning the transcript path and transcriptId. However, it does not explicitly state when not to use or list alternatives, so it falls short of a 5.

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