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

With no annotations provided, the description carries the full burden and does so thoroughly. It discloses platform-specific behaviors: Safari can list and drive tabs but cannot open or close them, and it 'error[s] on iOS rather than pretending.' It also warns that stale tabs accumulate across sessions, adding practical behavioral insight beyond the schema.

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, well-structured paragraph that front-loads the core purpose, then systematically covers platform constraints and a usage tip. Every sentence earns its place, with no redundancy or irrelevant detail, making it both concise and information-dense.

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 annotations and no output schema, the description is remarkably complete. It covers cross-platform behavior, error handling, the relationship between actions and parameters, and cleanup guidance. It even addresses the lack of switching on Safari by explaining direct targeting via pageId. The only minor gap is not describing the exact return structure of `list`, but it does mention that it returns a pageId per tab, which is adequate for the tool's complexity.

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 all six parameters are already documented. The description adds extra semantic value by explaining how pageId from `list` is used to target tabs in other webpage_* tools, clarifying the relationship between actions and the cross-platform implications of pageId. This goes beyond the individual parameter descriptions, though it doesn't detail every parameter's syntax.

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's function with a specific verb+resource: 'List, open, switch and close browser tabs on the device.' It also distinguishes itself from sibling tools by focusing on tab management and explaining that it consolidates what would otherwise be several tools into one.

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 explicitly explains when to use each action: `list` works on both iOS Safari and Android Chrome, while `new`, `select`, and `close` are Android-only and error on iOS. It also provides cross-tool guidance by noting that pageId can be passed to other webpage_* tools, and advises closing stale tabs, giving clear usage context and alternatives.

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