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

Annotations already declare readOnly=false, destructive=false and idempotent=false, so the safety bar is lowered. The description adds real blast-radius context by naming the four domains the look touches at once, but it never says whether an applied look replaces or stacks on existing captions/grade/transitions, nor how a second application behaves given idempotentHint=false.

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?

A single front-loaded sentence with no filler; the scope of the treatment comes first and the optional music clause comes last. Nothing is wasted or repeated from the annotations.

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 broad multi-domain mutation with a ten-value enum and no output schema, the definition is only minimally sufficient: it conveys scope but leaves look selection semantics, interaction with pre-existing edits, and expected result unaddressed. Annotations cover the safety profile, which keeps this from scoring lower.

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 75% (music, project_id and transition_sounds are documented in-schema) and the description only echoes the music behaviour, adding no new meaning. The biggest gap is the required 'name' enum of ten looks, which is undocumented in both schema and description, so an agent has no idea what 'cinematic_doc' or 'creator_punch' actually produce.

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 plus the breadth of the resource: it applies a coordinated treatment spanning captions, grading, texture and transitions, which tells an agent this is a bundled look rather than a single-attribute setter. It never distinguishes itself from near-neighbours such as apply_recipe, apply_format_pack, set_color_grade or set_caption_style, so an agent cannot confidently pick between them from this 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?

There is no when-to-use or when-not-to-use guidance and no named alternative, despite an obviously crowded sibling space (apply_recipe, apply_format_pack, set_intensity, set_caption_style). The only conditional phrasing covers music ('optional explicitly selected music'), which is a parameter note, not usage routing.

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