play_ab_tool

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

No annotations are provided, so the description must carry the full burden. It does disclose a side effect ('Leaves the history cursor on after_index') and a default ('Default gap is 0.4s'), which is helpful. However, it does not clarify whether extraction has side effects, whether dry_run actually suppresses playback, or whether the operation is blocking. Partial transparency.

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 sentences, each earning its place: core behavior, when to use, and a side effect plus default. No filler, front-loaded with the action. Highly concise and well-structured.

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 the complexity (9 params, 0% schema coverage, no annotations), the description leaves too much unsaid. It doesn't explain what start_sec/end_sec define, what dry_run does, what source options are valid, or what rerender means. An agent could not confidently call this tool correctly solely from the description, despite the output schema existing.

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 0%, so the description must compensate. It clarifies that before_index and after_index are history indices and mentions the gap default, but it leaves source, dry_run, start_sec, end_sec, and rerender completely unexplained. For a 9-parameter tool with no schema descriptions, this is insufficient.

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+resource: 'Extract the same range at two history indices, then play A→gap→B once.' This clearly differentiates it from sibling playback tools like play_audio_tool or play_compare_tool. The A/B comparison behavior is unique and unmistakable.

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 explicitly recommends using this tool over history_goto → play → goto → play for before/after probes. It names the alternative operation sequence and the specific use case. This is exactly the kind of routing guidance an agent needs.

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