Log in to MyChart

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

The description discloses key behaviors: visible browser window, direct user interaction for MFA, no credential passing through MCP, optional prefill from env vars, and persistent profile storage. These traits go well beyond the annotations, which only mark idempotency and open-world behavior.

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?

Each section, such as purpose, MFA tip, persistent profile explanation, and parameters, adds necessary context. The description is structured and front-loaded with the core action, making it easy to parse despite its length.

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 the tool's interactive login nature, the description covers prerequisites, user actions, session persistence, and return format. The explicit Returns line compensates for the missing output schema, and the detail about the browser profile ensures the agent understands side effects.

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 already fully documents timeout_seconds with default 300 and max 900, so the description's Args section repeats this. It adds no new meaning beyond what the schema provides, so baseline 3 applies.

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 action: opening a visible browser window at the MyChart login page and waiting for sign-in. This distinguishes it from siblings like mychart_list_test_results or mychart_session_status, which are post-login operations.

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 explains that all other tools work headlessly after this login, implying this is the prerequisite step. It also advises about MFA and session persistence, giving clear when-to-use context, though it doesn't explicitly mention alternatives like checking session status first.

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