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

With no annotations, the description carries the burden of behavioral disclosure. It discloses the main side effect (closing the session and its tab) and adds the useful lifecycle fact about idle expiration. However, it does not mention behavior for invalid/expired session IDs, idempotency, or whether closing is irreversible, so the behavioral picture is only partially complete.

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 short and front-loaded: the primary action is stated first, and the expiration note follows in a second concise sentence. There is no wasted wording, though the second sentence could arguably be positioned as part of usage context rather than the main operation.

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 simple one-parameter tool with no output schema, the description covers the core action and an important lifecycle behavior. Still, it lacks guidance on prerequisites, error handling, and how the session ID is obtained, and it does not explicitly route the agent away from the sibling tool when appropriate.

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%, and the description does not explain what session_id represents beyond the implied 'browser session' resource. It does not say where the ID comes from, what format it has, or what happens if it is invalid. The description adds very little value beyond the schema's bare parameter name.

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 uses a specific verb ('Close') and resource ('browser session') and adds that the tab is closed too. It is clear enough to distinguish from the sibling run_browser_task, though it does not explicitly contrast itself with that tool.

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?

There is no explicit guidance on when to call this tool versus run_browser_task or when closing is unnecessary. The expiration note ('Sessions also expire after 5 minutes idle') hints that explicit closing may not always be required, but it does not give clear when-to-use or when-not-to-use guidance.

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

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

With no annotations provided, the description carries the full burden, and it does so thoroughly. It discloses that results are evidence rather than verdicts, that verified is always false, and that page_text_untrusted may contain adversarial text that must be treated as data, not instructions.

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 dense but highly structured, with usage modes, return semantics, and a security warning packed into a compact set of sentences. Every sentence adds actionable information and important caveats are front-loaded.

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 output schema and no annotations, the description still tells the agent how to invoke the tool, how to continue or redirect a session, what evidence fields to inspect, and how to handle untrusted page content. Nothing essential for correct use is missing.

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 has 0% description coverage, so the description must compensate. It clearly explains url, goal, and session_id by mapping them to start/continue/redirect modes, but it does not describe timeout_s, leaving that parameter to its self-evident name and default value.

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 names a specific action and resource: 'Drive a browser toward a goal,' with clear modes (start, continue, redirect) and a precise statement of what it returns. It also distinguishes itself from fetching public content with a fetch tool, which helps an agent understand the tool's niche.

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 explains when to pass url and goal, when to pass session_id alone, and when to redirect with session_id and goal. It also gives a clear when-not-to-use rule: not for fetching public content readable with a fetch tool.

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