animation_fetch_recolor

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

With no annotations, the description carries the full burden and does so well: it discloses the asset source and license, the selection rule (most-viewed match), the deterministic color-mapping policy (dominant→primary, others→accent, black/white kept), and critically that recolor is build-time with no runtime Swift code. It omits failure modes (no match found), network/rate-limit behavior, and auth needs.

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 first sentence front-loads the action and destination, followed by compact source, recolor, and parameter notes. Usage of arrows and line-break fragments is dense but each sentence adds real information; only minor trimming is possible.

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?

An output schema exists so return values need not be explained, and the description compensates for 0% schema coverage across the non-obvious parameters. What remains missing is error/failure handling and any dependency on network access to LottieFiles.

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 largely does: slot is enumerated (loading | success | empty | onboarding_hero), keyword gets an example, and primary_hex/accent_hex get format rules ('#' optional, format hint '006A63'). app_dir is left undocumented but is self-evident from the output path.

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 two-part action (fetch + recolor a Lottie animation) and names the exact output artifact (Resources/Animations/<slot>.json), which no sibling tool produces. It is immediately distinguishable from nearby tools like mascot_assets, icon_generate, or design_generate.

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?

Gives clear context: the tool is called for every slot of every app, and the keyword parameter is for app-themed overrides. It does not explicitly name competing tools (e.g. mascot_assets, icon_generate) or state when NOT to use it, but the usage context is unambiguous.

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