State diff

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

Annotations already indicate this is a safe, idempotent read operation (readOnlyHint=true, destructiveHint=false, idempotentHint=true). The description adds that it deals with 'initial vs final' state differences, but doesn't clarify what 'initial' and 'final' refer to (e.g., frame boundaries, capture lifetime). This adds some context but not enough to fully characterize behavior beyond annotations.

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 a single 10-word sentence, concise and front-loaded. It is efficient but perhaps too brief; however, it earns its place by stating the core purpose without fluff.

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 no output schema, the description should explain the return format or behavior. It does not mention what the diff output looks like, and 'initial vs final' is ambiguous. The description is incomplete for an agent to fully understand what to expect.

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 description coverage is 0%, so the description must compensate. It only indirectly mentions the parameter through 'for a capture,' but does not explain the 'captureId' parameter's role or format. This adds minimal value beyond the schema's property name.

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 states the tool gets 'initial vs final GL state differences for a capture.' This is a specific verb and resource, and it distinguishes from siblings like webgl_diff_captures (which diffs two separate captures) by focusing on state within a single capture. However, it doesn't explicitly differentiate from tools like webgl_get_capture_overview.

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 provides no guidance on when to use this tool versus alternatives. With 38 sibling tools, including similar ones like webgl_get_capture_overview and webgl_diff_captures, the lack of usage context is a significant gap.

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