Extract local GIF frames

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

Annotations say readOnly=false and destructive=false but nothing about safety, verification or environment. The description adds real context: output is verified pixel-by-pixel, decoding is strict and aborts on damaged frames, a local browser is required for encoding (implying cost/latency), and frames are not scaled. It does not say what happens if output_dir already exists, which matters given idempotentHint=false.

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?

Five dense sentences, each adding a distinct fact (output, mode semantics, error policy, verification, environment constraint) with the primary outcome front-loaded. No filler or restatement of the tool name.

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 carries the return-value burden and does describe the artifacts produced (PNG directory + timing manifest). Missing details are modest: file naming convention, manifest format, and behavior on a pre-existing output directory for a non-idempotent writing tool.

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 50%, and the description compensates meaningfully by defining what 'composited' and 'stored' modes actually do rather than just listing the enum values. 'Selected or all frames' implies the purpose of the frames array but gives no indexing convention or bounds, which remains a 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?

States a specific verb, resource and output artifact: extract GIF frames into a new local directory of lossless PNGs plus a timing manifest. That output shape cleanly separates it from sibling GIF tools (abox_gif_inspect, abox_gif_create, abox_gif_to_mp4) without needing to name them.

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?

Explains the two modes and their defaults, which tells an agent how to configure a call, and 'strict decoding refuses damaged or partial frames' implies a failure mode. But it never says when to reach for this tool instead of abox_gif_inspect or abox_gif_to_mp4, so the alternative-routing guidance is left implicit.

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