immich-photo-manager

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

With no annotations provided, the description carries the full burden and does well by disclosing key behavioral traits: it describes the return format (JSON with 'data' and 'type'), performance characteristics ('fast' vs 'larger'), and default behavior. It lacks details on error handling or rate limits, but covers essential operational context adequately.

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 appropriately sized and front-loaded: the first sentence states the core purpose, followed by return format details, then parameter explanations. Every sentence earns its place with no redundant information, making it efficient and well-structured for quick comprehension.

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?

Given the tool's moderate complexity (2 parameters, no annotations, but with an output schema), the description is complete enough. It explains the purpose, usage, parameters, and return values, and since an output schema exists, it doesn't need to detail the JSON structure further. This covers all necessary context for effective tool invocation.

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 description coverage is 0%, so the description must compensate fully. It successfully adds meaning beyond the schema by explaining both parameters: 'asset_id' as 'The unique ID of the asset' and 'size' with its options ('thumbnail' or 'preview'), pixel dimensions, and default value. This provides complete semantic understanding of the inputs.

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 clearly states the specific action ('Get a base64-encoded thumbnail'), resource ('for a single asset'), and distinguishes from siblings like 'get_thumbnails_batch' (batch operation) and 'get_asset_info' (metadata retrieval). It precisely defines what the tool does without being vague or tautological.

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 provides clear context on when to use this tool (for retrieving thumbnails of specific sizes) and implicitly distinguishes it from batch operations like 'get_thumbnails_batch'. However, it does not explicitly state when not to use it or mention alternatives like 'get_asset_info' for non-thumbnail data, which prevents a perfect score.

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