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

Annotations only declare readOnlyHint true, so the description correctly adds behavioral details: it lists the output types, notes that it is free, and explains the 404 error meaning 'never scanned' with a recommended follow-up. This goes well beyond the annotation coverage, making the tool's behavior transparent.

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 compact—three sentences that each add value: the output content, the usage purpose, and the error handling. There is no fluff or redundant phrasing, and the most important 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 read-only tool with two parameters and no output schema, the description is complete. It covers what the tool returns, how to interpret an error, and what to do before using it, ensuring an agent can call it correctly without further context.

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?

The schema documents both parameters fully (target_id as 'Generation or asset id' and target_type with enum and default). The description does not add any additional parameter semantics, so the baseline score of 3 is appropriate given 100% schema coverage.

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 states exactly what the tool returns—item names, categories, textures, colors, and bounding boxes (0-1000 normalized) plus a scene narrative. It clearly differentiates itself from scan_image (a prerequisite) and explicitly connects to restyle by mentioning picking item names, making its 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?

Provides explicit usage context: use it to see image contents or to pick item names for restyle, and instructs to run scan_image first if a 404 is encountered. It does not explicitly mention 'when not to use' or name alternative tools like get_meta, but the guidance is clear and actionable.

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