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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds valuable context beyond annotations: it reads server-side entitlement, depends on Stripe's signed webhook, and never retries payment. No contradiction with annotations; it slightly over-delivers but still omits return-format details.

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?

Two sentences with zero waste. The usage instruction ('Use this after checkout') is front-loaded, and the follow-up action is embedded naturally. Every clause earns its place.

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 has no output schema, the description gives a hint about the response (implying a 'paid' field) and clearly states the activation condition. It covers the essential trigger and next step. It doesn't spell out the full return payload, but that's acceptable given the simple nature and the hint provided.

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% and the only parameter (onboarding_token) is fully documented with a pattern and description. The tool description adds no additional parameter semantics beyond referencing the post-checkout context. Per the baseline for full schema coverage, a 3 is appropriate.

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 tool checks subscription status after checkout, specifically whether Stripe's webhook has activated the account. It uses a specific verb and resource and distinguishes itself from siblings like create_subscription_checkout and connect_congressmcp_account by framing itself as a read-only check.

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 says 'Use this after checkout' and instructs the agent to call connect_congressmcp_account when paid is true. It also states what the tool never does (retry payment or change billing), effectively precluding misuse. This is strong when/when-not guidance with an identified alternative.

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