compare_frames

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

With no annotations, the description carries the full burden of behavioral disclosure. It states the output format (JSON metrics) and implies a read-only operation, but does not clarify whether frames are flattened internally, what happens on invalid input, or any side effects. Some useful context (flattened frames) is given, but more could be said.

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?

A single sentence that is front-loaded with the purpose and contains no filler. It is concise and easily scanned.

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?

Given three parameters, no output schema, and no annotations, the description is incomplete. It does not specify what 'changed-pixel metrics' includes (e.g., counts, bounding boxes, thresholds), nor does it mention error handling or edge cases. An agent would need more guidance to reliably interpret the result.

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%, so the description must compensate. It mentions 'two flattened animation frames' which maps to frame_a and frame_b, and 'filename' is implied, but it does not explain that these are integer frame indices or what the filename refers to. The description adds minimal meaning beyond the schema.

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 ('Compare'), a clear resource ('two flattened animation frames'), and the output ('changed-pixel metrics as JSON'). It is unambiguous and distinguishes itself from all sibling tools, none of which perform frame comparison.

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?

The description implies when to use the tool (whenever you need to compare two frames), but provides no explicit context, alternatives, or exclusions. Since there are no other comparison tools among siblings, the usage is fairly obvious, but the description does not articulate it.

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