View asset thumbnail

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

Annotations already declare readOnly, idempotent, non-destructive, open-world. The description adds non-obvious behavior the annotations cannot convey: a size-dependent redirect to downloadAsset and the differing permission requirement that follows. It stops short of describing the returned payload or authentication needs.

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?

Front-loaded with the action and scope in one sentence, followed by a useful caveat; the trailing 'Immich operation / tag' line is boilerplate but compact. No wasted prose.

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 no output schema the description should say more about what comes back (binary image vs URL) and which permission is required. It partially covers this via the downloadAsset redirect note, but an agent still lacks the return-shape and permission details needed to call it confidently.

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 only 60% and the description adds no parameter meaning at all — id, key, slug, size and edited are never discussed. 'The specified asset' gestures at id but gives no guidance on the size enum or what edited/key/slug do, so the description does not compensate for the coverage gap.

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 a specific verb and resource ('Retrieve the thumbnail image for the specified asset') and even hints at the boundary with the sibling downloadAsset. It is clear what the tool does, though it never explicitly contrasts with immich_get_asset_file, which is the other likely candidate for an agent.

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?

Usage is implied by the redirect caveat ('Viewing the fullsize thumbnail might redirect to downloadAsset, which requires a different permission'), which tells the agent one condition where behavior changes. However there is no explicit when-to-use / when-not-to-use guidance versus immich_download_asset or immich_get_asset_file.

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