capture_set

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 pages default to all reference names, that specific pages work if the route mapping resolves them, and the outcome it proves. This adds significant behavioral context beyond the schema, though it does not mention return format, side effects, or requirements. Given the lack of annotations, this is reasonably transparent.

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 concise, three sentences, and front-loads the main purpose. It includes a concrete example and flows logically. It is not overly verbose, though it could have added a bit more structure, but it's effective and efficient.

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 five parameters with zero schema descriptions, no annotations, and no output schema, the description is incomplete. It explains only label and pages, leaving profile, base_url, and viewport unexplained. It also does not describe what the tool returns or any side effects. An agent would need more information to use it confidently.

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 explains the label parameter (via the example) and pages (default behavior and condition), but it does not explain profile, base_url, or viewport at all. With five parameters and no schema descriptions, covering only two is insufficient, leaving the agent guessing about the rest.

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 clear verb and resource: 'Capture a named set of pages' with a label. It provides an example use case (label='before'/'after' around a refactor) and distinguishes it from other tools by implying it captures a set under a label rather than a single capture. However, it does not explicitly name sibling tools to differentiate, though it references compare_sets, so it's clear enough.

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 gives clear usage context: 'Use compare_sets afterwards' and the purpose 'Proves a refactor is pixel-neutral without depending on golden references.' This tells the agent when to use it (refactor verification). It does not explicitly state when not to use it or mention alternatives, but the context is clear and actionable.

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