Get media progress

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

The annotation readOnlyHint=true already indicates this is a safe read-only operation. The description adds helpful behavioral detail: it returns a 404 when the item has never been started, which is beyond what annotations provide. It also mentions the return includes position, percentage, and finished status. There is no contradiction with the annotation.

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, informative sentence that front-loads the key purpose and then adds the important error behavior. It uses no filler words and every piece of information is relevant and non-redundant with the schema or annotations.

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?

Given there is no output schema, the description sufficiently explains the return fields (position, percentage, finished status) and error case. However, it does not mention what happens for an unfinished book (e.g., does it return partial progress) or if there are any rate limits or performance considerations. For a simple progress-checking tool, this is mostly complete, but could clarify the unfinished behavior.

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 schema description coverage is 100%, so the baseline is 3. The description adds value by explaining that 'compact' (default) returns a projection for browsing and 'full' returns a very large raw object with audio files, tracks, and chapters — crucial context for selecting the appropriate detail level. It also clarifies that episode_id is required for podcasts but omitted for books, and explains where to get library_item_id. This goes beyond the schema's bare descriptions.

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 that this tool returns the listening progress of the current user for a specific book or podcast episode, including position, percentage, and finished status. It also specifies that it returns a 404 error when the item has never been started, which is a clear behavioral note that helps distinguish it from other tools.

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?

While the description is clear about what the tool does, it does not provide when or when-not to use this tool compared to its many siblings. For example, it is not noted that list_items_in_progress might be a better choice for browsing progress across all items, nor are any prerequisites or alternatives mentioned. The guidance is implied in the tool's name and description but lacks explicit usage context.

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