open_upgrade_checkout

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

No annotations provided, so description carries full burden. It discloses that shell.openExternal launches the browser, the return format ({ ok, url, sessionId, opened }), and that sign-in is required. Provides sufficient transparency for an upgrade action.

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?

Description is moderately concise and front-loaded with the main purpose. It contains necessary details but could be slightly tighter. Still, every sentence adds 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?

Complete for a checkout tool: explains the return value, how to interpret opened, the prerequisite (sign-in), and the follow-up action. No output schema exists, but the description covers what the agent needs to know.

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%, but description adds context by listing the allowed enums and providing example usage. It reinforces the meaning of tier and billing_type beyond the schema's descriptions.

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?

Clearly states what the tool does: opens a Stripe Checkout page for upgrading to a paid tier. Provides concrete example intents ('upgrade me', 'I want pro') and distinguishes from sibling tools like open_billing_portal and get_my_plan by specifying when to use it.

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?

Explicitly tells when to use (user intents like 'upgrade me') and what to do after calling (call get_my_plan). Could more explicitly state when not to use, but the context is clear enough.

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