probe

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

With no annotations, the description carries the full burden. It discloses that it saves numbers as JSON to a report folder and returns a short summary, which are behavioral traits. It does not mention side effects or permissions, but it clearly indicates it produces a file and a summary.

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 sentences, front-loaded with the main action and metrics, followed by return behavior and usage. No wasted words.

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 single-parameter tool with no output schema and no annotations, the description covers the main aspects: what it does, what it returns, and when to use. It could detail the summary format but that's minor.

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?

The schema already describes the 'name' parameter with its role in file naming. The description adds no further meaning beyond the schema, so with 100% coverage, baseline 3 applies.

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 'Measure' and resource 'current page', and enumerates exact metrics (contrast, button size/position, icon buttons without names, dead links, unlabeled form fields, decoration). This clearly distinguishes it from siblings like screenshot or capture, which focus on visual capture rather than quantitative measurement.

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 explicitly says 'Use it on each screen you judge', providing a clear context for when to invoke the tool. It does not name alternatives or exclusions, but the instruction is sufficient for an agent to know this is the measurement tool for evaluation.

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