browser_login

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

With no annotations, the description carries the full behavioral burden well: it discloses that auto sites use stored credentials without exposing values, manual sites return needs_human, it tries only once, and retries are avoided because they lock accounts. It also states the login happens in a new tab.

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 compact and front-loaded: purpose first, then auto-site behavior, manual-site/failure handling, and retry constraint. Every sentence adds operational value.

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 two-parameter tool with no annotations and no output schema, the description covers the key behavior: login attempt, credentials handling, needs_human fallback, and no-retry policy. It could be slightly more complete about the success signal, but nothing critical 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?

Schema coverage is 50%: the port parameter has a detailed schema description, but site has none. The tool description adds useful site-category semantics (auto vs manual) but does not clarify site format or examples, so it only partially compensates.

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?

States a specific action and resource: make sure the session for a site is logged in, in a new tab. It distinguishes auto sites from manual sites and explains the needs_human fallback, so an agent can tell what this tool is for without opening the schema.

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?

Gives clear operational guidance for manual sites and failures: returns needs_human, then stop and ask the human to log in in that Chrome window. It does not explicitly name alternatives such as browser_open or login_sites, but the when-to-use context is strong.

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