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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds substantial behavioral context beyond that: presigned URLs expire in ~1h, the in-app preview may differ from the downloaded bundle, and the top-level animationQualityGate semantics (ready/needs_review/unscored) are explained. It also discloses the collision-body resolution order and the normalization to full untrimmed frameSize. No contradiction with annotations.

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 description is dense but every sentence earns its place: it front-loads the return payload, then covers usage guidance, quality gates, collision resolution, coordinate normalization, URL expiry, and validation caveats. It is longer than a typical description, but the tool is complex and the content is high-signal. A small amount of redundancy (e.g., 'download immediately, never store or commit one') could be tightened, but the structure is logical.

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 read-only getter with one parameter and no output schema, the description is remarkably complete. It covers the return payload, the meaning of quality gates, collision-body resolution, coordinate normalization, URL expiry, and the preview-vs-bundle caveat. An agent has everything it needs to call the tool and interpret the result correctly.

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% and the only parameter, characterId, is documented in the schema. The description doesn't add parameter-level detail beyond what the schema provides, but with a single required string parameter there is little more to say. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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 opens with a precise inventory of what the tool returns ('full PhaserCharacter JSON: animations, frameSize, gameType, animationDirection, per-group atlas + spritesheet URLs, poses and mount points'), which clearly distinguishes it from sibling getters like get_character_manifest or get_asset. The verb 'get' plus the named resource and the explicit content list make the purpose unmistakable.

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?

The description gives explicit when-to-use guidance: preselect animationDirection before asking for directional animation generation, follow needs_review actions before claiming readiness, and check collision bodies in a specified order. It also tells the agent what not to do (never subtract atlas offsets, never store/commit presigned URLs). This is far beyond a minimal 'use this to fetch a character' statement.

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