Retrieve faces for asset

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is fully covered elsewhere. The description adds only the underlying REST operation (GET /faces) and tag, with no information about return contents, pagination, or permission requirements.

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 opening line merely restates the title and is immediately restated again in the second sentence, so roughly half the text is redundant. The useful content (endpoint, tag) is at the end rather than front-loaded, but the whole thing is short enough not to be a burden.

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?

With one parameter, no output schema, and full annotation coverage, the description is minimally adequate. It could have said what a returned face comprises (person reference, bounding box) or clarified the id/asset ambiguity, but nothing critical to invoking the tool is missing.

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 100% for the single required parameter, so the baseline is 3. The description adds nothing beyond the schema and arguably muddies it by saying faces belong to an 'asset' while the parameter is documented as a 'Face ID'.

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 verb and resource ('Retrieve faces for asset') and repeats it as 'Retrieve all faces belonging to an asset', so the operation is unambiguous. It does not distinguish itself from nearby siblings such as immich_get_person, immich_search_person, or immich_reassign_faces, and the schema's 'id' is labeled 'Face ID' while the prose talks about an asset, leaving a small ambiguity about what is being looked up.

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?

No when-to-use, when-not-to-use, or alternative guidance is given. The agent must infer from the name alone whether this is the right call versus immich_get_person or immich_search_person. The only routing hint is the raw endpoint and tag, which is not user-facing guidance.

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