capture_playback_position

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

With no annotations, the description discloses the key behavioral facts: it writes a local sidecar JSON file under the backup dir and never touches Spotify. This tells the agent the operation is local, state-persisting, and safe relative to Spotify, which is exactly the behavioral context needed.

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?

Two focused sentences, front-loaded with the action and end state, with no filler. The local-sidecar clarification earns its place because it affects the agent's expectations.

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 low-complexity tool with two optional documented parameters and a clear pairing with resume_playback_position, everything needed to select and call it is present. No output schema exists, but the description makes the operation and its persistence location sufficiently 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%, so both parameters are already documented. The description adds no parameter-specific detail beyond the schema, making the baseline 3 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?

States a specific verb ('Bookmark') and resource ('current track, playback position and device to a local JSON file'), and names the paired resume_playback_position tool. This clearly distinguishes capture_playback_position from playback-resume and bookmark-management siblings.

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?

Explains the intended workflow: bookmark now, resume later with resume_playback_position. It does not explicitly list exclusion criteria or compare against alternatives like save_playback_state, checkpoint_playback, or list_playback_bookmarks, so the guidance is clear but not exhaustive.

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