Plan Speaker Checkerboard

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

Annotations already declare readOnly/idempotent/non-destructive, and the description reinforces 'never changes Premiere' while adding value beyond the annotations: it discloses the return payload (frame-snapped segments, split points, track assignments) and the downstream route names (add_track/razor_all_tracks/move_clip_to_track). It does not discuss limits or failure modes, but the annotation bar is already met.

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 dense sentences: purpose first, then output/routes, then the safety constraint last. No filler, and the most decision-relevant information is front-loaded.

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 complex 9-parameter, nested-object tool this is largely complete: it names the input source, the transformation, the outputs, and the safety profile. Since an output schema exists, return-value detail is redundant rather than missing, and the only small gap is explicit routing away from sibling planners.

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 100% with 9 well-documented parameters including nested word_timeline entries, so the schema carries parameter meaning. The description only references the 'word timeline' input and 'frame-snapped' behavior, adding little beyond the structured fields — the baseline 3 for full coverage is 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 (Plan) and resource (speaker checkerboard), then parenthetically defines the concept (each speaker's turns on their own video/audio track) so the agent need not infer it. Clearly distinguishable from siblings like plan_multicam_angle_switches and plan_active_speaker_reframe.

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?

Specifies the input precondition (a caller-supplied word timeline) and notes it is local-only, giving clear usage context. However, it never states when to prefer this over adjacent planning tools such as plan_multicam_angle_switches or plan_active_speaker_reframe, so alternative selection is left to inference.

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