browser_http_auth

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

With no annotations, the description carries the full burden. It discloses key behaviors: the tool arms answers, scopes to the secret's domains, never accepts or returns the credential value, and must be called pre-navigation. It does not mention failure modes (e.g., missing alias) or the exact behavior when 'once' is not set, but the essential security properties and invocation timing are clearly stated.

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 sentences, no wasted words. The core purpose is front-loaded, followed by a security constraint and a direct usage instruction. It is optimally concise while conveying all necessary operational context.

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 two-parameter tool with no output schema and no annotations, the description covers purpose, security, scoping, and timing. It does not describe return values (likely none) or error handling, but these are not critical for an agent to invoke it correctly. The absence of a return description is acceptable given the tool's nature.

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% with descriptions for both 'secret' and 'once'. The description adds value by reinforcing that 'secret' is an alias, not a value, and that the credential value is never accepted or returned. This goes beyond the schema's 'Secret alias from the server-side secrets vault.' The 'once' parameter is already well-described in the schema, so the description does not need to expand on it.

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 states a specific verb and resource: 'Arm answers for HTTP basic-auth prompts' using a server-side secret alias. It clearly distinguishes the tool from siblings like browser_fill_secret (which would input credentials directly) and browser_clear_http_auth by emphasizing the alias-only approach. The scope ('scoped to that secret's domains') adds precision.

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?

Provides a clear when-to-use instruction: 'Call before navigating to the protected URL.' It implies the alternative (not calling leads to a native dialog) but does not explicitly name sibling alternatives or conditions for when not to use. The security-focused phrasing ('never accepted as input or returned') implicitly contrasts with tools that accept credential values, but a direct comparison is missing.

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