Snapshot a shared tab

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

Adds substantial behavior beyond annotations: form values are never returned, hidden controls are excluded, output can be truncated (pointing at 'coverage'), taking the claim makes refs actionable while invalidating earlier refs, and credential fields are flagged. That claim/staleness interaction is exactly the non-obvious behavior an agent needs.

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?

Three dense sentences, no filler; scope first, then exclusions/limits, then the claim semantics, then the credential safety rule. Every clause carries operational meaning.

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?

No output schema exists, yet the description covers return content (refs), what is omitted (values, hidden controls), truncation with a pointer to coverage, and the safety-relevant credential rule. An agent can call this correctly and interpret the result without further context.

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 100%, so baseline is 3, but the description goes further by tying claim=true to ref usability and the staleness of prior refs — consequences the schema's one-line description does not convey. context_id and browser_instance_id get no extra treatment, which keeps it from a 5.

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?

Opens with a specific verb and resource — 'Read the interactive controls of a shared tab' — and immediately enumerates what counts as a control (links, buttons, fields, labels). This distinguishes it from browser_screenshot (pixels) and browser_click/fill (actions on refs) 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 claim=true default versus false for a 'read-only look', which is the key usage fork, and states the constraint that CREDENTIAL fields must be filled by the user rather than the agent. It never explicitly routes against sibling tools, so it stops short of a 5.

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