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

Annotations already declare it as a non-read-only, idempotent, non-destructive, closed-world mutation. The description adds genuine behavioral context beyond that: it may replace an existing treatment, ramps are frame-based entrances/exits, and the effect is confined to the window so the rest of the picture is untouched. It still omits what happens on conflicting/overlapping windows and what the call returns.

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?

Two tight sentences, front-loaded with the mutation and its time-window scope, followed by the containment guarantee. No filler and no restatement of the title.

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 15-parameter tool with nested objects, one enum, no output schema and 40% schema coverage, the description covers the windowing and protection mechanics but leaves the color-correction parameter set and the stage scoping unexplained. It is adequate to understand the tool's shape but not sufficient to invoke it confidently without reading the schema.

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 only 40% across 15 parameters, so the description must carry weight. It usefully explains the window (start/end as program time), ramp_in_f/ramp_out_f as frame-based ramps, and region/protect as regional and skin/brand protection. It says nothing about the color parameters (ev, tint, contrast, saturation, split_tone, temperature), the world/screen stage enum, or the id field, leaving a substantial documentation gap.

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 gives a specific verb and resource: it sets or replaces a color treatment scoped to a program-time window, with ramps and optional region/skin-brand protection. That is clearly distinguishable in intent from a whole-frame grade, but it never names the adjacent siblings (set_color_grade, set_grade_custom, match_grade, apply_look) that an agent must choose between.

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?

There is no explicit statement of when to reach for this tool versus the other grading tools, nor any prerequisite such as an existing grade or project state. The clause 'picture outside the window remains unchanged' hints at windowed-local use, but the agent must infer the selection rule entirely.

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