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

Goes well beyond the annotations (readOnlyHint=false, idempotentHint=false, openWorldHint=false) by disclosing the side effect (an email is sent to the user), the human approval/code-match step, the required 15s polling of claim_api_key, and the cost terms (250 free credits/month, no card, existing plan carries over). This is exactly the behavioral context an agent needs before invoking.

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 core action is front-loaded and nearly every clause carries needed information (side effect, next step, cost). It is a dense run-on chain rather than cleanly segmented sentences, which slightly hurts scannability, but little is wasted.

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?

With no output schema, the description compensates by explaining the returned code and the request_id/claim_secret needed for claim_api_key, plus cost and auth context. It does not cover error/failure handling, so it is strong but not fully complete.

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 description coverage is 100%, so both email and client_name are already documented with format details and intent. The description only restates 'give the user's email address' and does not add meaning to client_name, so the baseline 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?

States a specific verb and resource ('Start sign-up', 'request_api_key') and explains the concrete outcome: gankdat emails the user a one-click approval link. It is clearly distinguishable from the query siblings and explicitly links to claim_api_key as the follow-up step.

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?

Tells the agent exactly when to use it (start sign-up from inside the agent), what to do afterward (show the code, then poll claim_api_key every 15s), and the precondition that it is free and needs no existing key. The workflow routing to the sibling tool is explicit.

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