set_word_timing_tool

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

With no annotations, the description carries the full burden and does well: it discloses that bounds are validated against the recording, that neighbour overlaps surface in context.warnings, that the operation submits SetTranscriptWordTiming, and that it is undoable. It omits permission/authorization requirements and any rate or concurrency behavior, 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 core action and units are front-loaded in the first sentence; the remaining sentences each add a distinct operational fact (indexing, guard, validation, warnings, undo). No filler and no repetition of schema structure.

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 mutating tool with no annotations and an existing output schema, the description covers validation, failure-guard behavior, warning surfacing, and undoability. It leaves authorization requirements and the role of project_path unstated, but nothing needed to call it correctly is missing.

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% across 7 parameters, so the description must compensate. It meaningfully explains word_index, source_id, and expected_text (refuse-on-edit guard), but says nothing about track_id, project_path, or the units/constraints of start and end beyond 'source seconds'.

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 and resource: set one transcript word's start and end in source seconds, with the Studio 'Adjust word timing' framing. It is clear enough to distinguish from edit tools like cut_words_tool or set_word_suppressed_tool, though it never names a sibling to contrast against.

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?

It covers conditional usage of parameters (word_index resolves against the track transcript, or the source_id recording's transcript when given) and the expected_text guard, which is genuinely useful routing information. However, there is no explicit when-to-use / when-not or named alternative among the many sibling word- and transcript-level tools.

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