allow_navigation

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

No annotations are provided, so the description carries the full burden. It discloses that the guard blocks by default and never auto-permits, and that the tool is for a single navigation. It does not mention idempotency or error conditions, but for a simple tool, this is adequate.

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: one sentence for purpose, followed by a brief explanation. It is well-structured with no unnecessary information.

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 tool with no output schema and 0% schema description coverage, the description covers purpose, usage guidelines, and basic parameter meaning. It lacks return value or error details, but is mostly complete for the 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 description coverage is 0%, so the description must add meaning. It briefly describes parameters: 'Active session ID' and 'The URL to permit navigation to.' This adds minimal semantics beyond the parameter names, but is acceptable for two simple params.

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 purpose: 'Permit a single cross-origin navigation that was blocked by the navigation guard.' It specifies the verb (permit), resource (cross-origin navigation), and context (extension mode), distinguishing it from siblings like browse or check_extension.

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 states when to use: 'Only needed in extension mode when allowed_domains is set and the agent navigates to an unlisted domain. The guard never auto-permits — this tool requires explicit agent invocation.' This provides clear context and exclusions.

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