Get person thumbnail

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered. The description adds only that a 'thumbnail file' is retrieved, hinting at a binary/image return rather than JSON, but says nothing about auth requirements, response content type, or error behavior for a missing person.

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?

Short and front-loaded, but 'Get person thumbnail' and 'Retrieve the thumbnail file for a person' are near-duplicates of the title, so a sentence is spent restating what the agent already sees. Still compact and easy to scan.

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 one-parameter read tool with annotations covering the safety profile and no output schema, most needs are met. However, for a file-fetching tool the description never clarifies that the response is binary image content or how it should be consumed, leaving a relevant gap.

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% (the sole 'id' parameter is documented as a uuid), so the schema carries the weight. The description adds no meaning about the id — that it must reference an existing person or where to obtain one — so baseline 3 applies.

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+resource: 'Retrieve the thumbnail file for a person', plus the underlying REST operation and tag. An agent can distinguish it from immich_get_person or immich_get_profile_image. It does not explicitly name siblings, so it stops short of 5.

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 guidance, no prerequisites, and no routing to alternatives such as immich_get_person or immich_get_profile_image. The agent must infer entirely from the name that this is for fetching only the person's thumbnail image.

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