ecamm_thumbnail

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered structurally. The description adds the meaningful detail that only the *last* thumbnail is returned, implying no history or versioning, but says nothing about permissions, failure modes, or freshness of the cached image.

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?

Two compact sentences with the resource stated first and the per-kind reference rules second; no filler, no repetition of the title or annotations.

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 two-parameter read-only tool with no output schema, the description covers the essentials: what is fetched and how each target is addressed. The main gap is the return form (image bytes, URL, or file path) and ambiguity behavior for name-based refs.

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 0% and neither parameter is documented in the schema, so the description does real work: it explains that scene/overlay refs accept a name or id while video refs require a file path. That is valuable but incomplete — it never states the accepted id format, path conventions, or what happens on an ambiguous scene name (does it resolve or error?).

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 names a specific resource ("last thumbnail image") and scopes it to three target types (scene, overlay, video), which is enough for an agent to know this is a thumbnail retrieval tool rather than a list or setter. It does not explicitly contrast with siblings like ecamm_list_scenes, so it stops short of a 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?

There is no statement of when to call this versus alternatives such as ecamm_list or ecamm_status, and no preconditions noted (e.g., that a video must already be loaded). It only tells how to reference the target, which is parameter guidance rather than usage guidance.

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