browser_capabilities

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false. The description usefully adds that results distinguish actual availability from live validation and entitlements, but it does not explain the probing mechanism, latency, return shape, or why idempotentHint is 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?

The definition is a single front-loaded sentence with no filler. It is dense and somewhat jargon-heavy, but it is appropriately sized and does not waste sentences.

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?

This is a low-complexity read-only probe with fully described parameters and safety annotations. Still, there is no output schema and the description does not say what a capability report contains or how availability results are grouped, leaving a meaningful gap.

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 100%, so both optional parameters are documented in the schema. The description adds no meaning about target_id or expected_layout_id or how they affect capability probing, so the baseline of 3 is appropriate.

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?

It states a diagnostic action ('probe') and a reporting outcome ('report actual availability'), but 'known native browser interfaces' is jargon and the scope is left vague. No sibling tool is named, so the agent must infer how this differs from browser_list_tabs, security_status, or other diagnostic tools.

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?

Usage is implied: use this to check capability availability, and the result separates availability from live validation and account entitlements. However, there is no explicit when-to-use/when-not-to-use guidance and no named alternative among the many browser and diagnostics siblings.

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