ass_karaoke_retime

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

With no annotations, the description carries the full burden and largely meets it: it discloses that the line's own Start/End are overwritten, that mode='even' vs 'proportional' changes distribution, that an impossible span raises ToolError, and that dry_run computes without writing. The mismatch-not-stretched policy is also stated. It omits permission/undo implications and any concurrency notes, keeping it short of a 5.

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 purpose is front-loaded and the Arguments/Returns sections are well organized with per-parameter labels. It is somewhat long and includes a verbose return-shape block plus a parenthetical aside, but those earn their place because no output schema exists and the parameter coverage is zero.

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 nine-parameter mutation tool with no annotations and no output schema, the definition supplies both parameter semantics and the full return structure, including the lines_changed and reported_not_stretched fields. It is nearly complete, missing only doc_id handling and the format expected by selection.

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 coverage is 0%, so the description must compensate, and it documents eight of the nine parameters (selection, mode, new_start_ms/new_end_ms, shift_ms, factor, min_cs, dry_run) with real semantics, including the enum values 'proportional'/'even' the schema lacks. Only doc_id is left unexplained, so the compensation is strong but not complete.

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 opens with a specific verb+resource: 'Retime existing karaoke to a new span, reporting each syllable before/after.' This clearly distinguishes the operation from tangential tools like ass_update_line. However, it never distinguishes itself from close siblings such as ass_karaoke_scale, ass_karaoke_shift, or ass_karaoke_set_timings, all of which also alter karaoke timing, so an agent cannot route between them from the text alone.

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?

Usage is only implied by the purpose statement ('retime existing karaoke to a new span') and the parameter narratives describing the two modes. There is no explicit when-to-use / when-not-to-use guidance and no naming of the alternative tools (ass_karaoke_scale, ass_karaoke_shift) that would tell an agent which retiming entry point to pick.

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