unifi_protect_get_event_thumbnail

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

Beyond the readOnlyHint annotation, the description discloses several important behaviors: it writes to disk by default, can return inline instead, consumes significant context in image mode, returns 404 for missing thumbnails, and creates parent directories for savePath. This is rich and useful behavioral information.

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 and front-loaded: purpose first, then output modes, then input source. Each sentence earns its place, and there is no redundant or vague wording.

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 adequately explains the return behavior: file path by default or inline image. It also covers error conditions, input provenance, and parameter options, making the tool fully understandable for correct 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?

Schema coverage is 100%, and the description still adds value: it explains that eventId comes from list_events, that hasThumbnail: true indicates an image exists, that output=image costs significant context for vision models, and that savePath parent directories are created. These go beyond the raw schema descriptions.

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 identifies the verb and resource: fetch the still image captured for a Protect event. It distinguishes this from event metadata and from sibling tools like get_camera_snapshot or get_event_thumbnails by specifying the event-triggered still frame.

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?

It gives clear context on when to use the tool: pass an event id from unifi_protect_list_events and prefer events with hasThumbnail: true. It also explains the output=image alternative for vision models. It does not explicitly name sibling alternatives or state when not to use them, but the usage context is strong.

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