fl_stop

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

The description adds a sequenced behavior beyond the annotations: it stops, rewinds to zero, and verifies both playing and normalized-position fields. Annotations already convey mutability and destructiveness, and the description's added verification step is valuable context rather than a contradiction.

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?

One front-loaded sentence states the action, the target state, and the verification behavior with no filler. Every word earns its place, making this a model of concise tool documentation.

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 tool with rich annotations and an output schema, the core behavior is fully captured. The main missing piece is a short note on expected_before's pre-condition role and the session_fingerprint concurrency guard, but those are already described in the schema, so the description remains adequate rather than incomplete.

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 input schema already documents expected_before and session_fingerprint; the baseline stays at 3. The phrase 'verify both fields' maps loosely to playing and song_position_normalized, but it does not explain how expected_before acts as a pre-condition or how the session fingerprint gates the write, so the description adds little beyond the schema.

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 specifies a concrete action sequence—stop playback, rewind to normalized position zero, verify the resulting state—so the tool's purpose is unambiguous. This combination clearly differentiates fl_stop from granular siblings like fl_set_playing and fl_set_song_position, even without naming them.

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?

No guidance is given about when to prefer fl_stop over related control tools, nor any prerequisites or exclusions. The agent must infer the use case from the name and sibling list, which is exactly what the description should have made explicit.

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