vendor_login

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

With no annotations, the description carries full burden. It discloses all significant side effects: opening a real Chromium window, best-effort prefill, user solving reCAPTCHA, capturing the login response, updating the in-memory cache, and writing tokens back to .env. It also reveals blocking behavior up to 10 minutes, which is critical for agent expectations.

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 well-structured with a summary, explicit usage conditions, and a numbered flow. Every sentence adds operational value (prefill, captcha, cache, .env, blocking) without fluff, making it easy to parse and act on.

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?

Covers the full lifecycle: triggers, user interaction steps, backend side effects, persistence, and timeout behavior. No output schema exists, but the description sufficiently explains what happens during and after execution, making it complete for an interactive login tool.

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 input schema has zero parameters, so there is nothing to elaborate. The baseline of 4 applies because the description correctly implies no parameters are needed, and no additional semantic explanation is required.

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 opens with a specific verb phrase ('Open a real Chromium window') and identifies the exact resource (vendor frontend) and goal (user login). It clearly distinguishes this from sibling read-only tools like auth_status and get_current_user by describing an interactive login flow.

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 explicit 'Use this when' conditions tied to auth_status=false or token errors, making it unambiguous when to invoke. The numbered flow also clarifies the expected sequence and user involvement, effectively indicating when this tool is appropriate.

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