play_at

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 meaningful behavioral traits: it is a single write operation ('🟢 (1 write)') and it wraps the PUT /me/player/play endpoint with offset/position_ms. However, it omits consequences such as whether current playback/queue is replaced, device requirements, or what happens when no context is supplied.

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?

Three short sentences with zero filler. The core purpose is front-loaded, and the endpoint plus write-count are conveyed compactly. Every sentence earns its place.

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?

The core function and position formats are conveyed, which is adequate for a minimum viable definition. But with 9 parameters, no annotations, no output schema, and a crowded playback sibling group, the description is missing usage-routing and side-effect context that an agent would need to invoke it confidently.

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 100%, so the baseline is 3; the schema already documents all 9 parameters. The description adds a compact summary of accepted time formats (H:MM:SS / MM:SS / seconds / position_ms), but this largely duplicates the schema's 'at' and 'position_ms' entries and adds nothing about the relationship between at/position_ms and offset/offset_uri or the dry_run behavior.

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 verb and resource: 'Start playback at a specific position', and enumerates accepted position formats. However, it does not differentiate from closely related siblings like play, play_on, seek, seek_relative, or continue_last; the mention of wrapping PUT /me/player/play is a mechanism hint rather than a contrast.

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?

There is no when-to-use or when-not-to-use guidance. Given the large family of playback siblings (play, play_on, seek, seek_relative, continue_last, checkpoint_playback), an agent receives no routing criteria to select this tool over alternatives. The only implicit signal is that this tool combines starting playback with a target position.

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