list_playback_bookmarks

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

There are no annotations, so the description carries the full burden. It explicitly states 'Read-only', discloses that data lives 'stored locally under the backup dir', and specifies ordering as 'newest last'. This gives meaningful behavioral context beyond the schema, though it does not detail edge cases like empty results or exact return shape.

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 efficient sentence that front-loads the core action ('List all captured playback bookmarks'), then adds essential scope, ordering, and safety information. There is 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 two-optional-parameter read-only list tool with full schema coverage, the description provides enough to select and invoke correctly: it states the data source, read-only nature, and ordering. It does not explicitly describe the return value, but 'List all...' plus the response_format parameter makes the expected result reasonably clear.

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%, and both max_results and response_format already have detailed descriptions in the input schema. The tool description adds no parameter-specific meaning, so the baseline score of 3 is appropriate.

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 uses a specific verb ('List'), names the exact resource ('captured playback bookmarks'), and adds scope ('stored locally under the backup dir') plus ordering ('newest last'). This clearly differentiates it from sibling tools like delete_playback_bookmark, capture_playback_position, and resume_playback_position without needing to open their schemas.

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 clear context: this is a read-only listing of locally stored bookmarks, so an agent knows it is for inspection rather than mutation. It does not explicitly name alternatives or when-not-to-use conditions, but the context is sufficiently clear for a simple list-all operation.

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