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

Annotations provide idempotentHint=true, and the description aligns by framing this as a message-returning step rather than a side-effectful binding action. It adds useful context beyond the annotations: the exact JSON return fields, expiration behavior, the need to follow with bind_key_complete, and the API-key requirement. A minor gap is not spelling out the consequence of using an already-bound key, though it does say not to.

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?

Every sentence carries weight: purpose, use case, exclusions, return shape, next step, and auth requirement are all packed into a compact paragraph. The core outcome is front-loaded, and there is no filler or repetition.

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?

For a single-parameter start-step tool with no output schema, the description supplies the return fields, expiration, the mandatory follow-up step, the auth requirement, and the conditions under which it should not be used. Nothing essential for correct invocation is missing.

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%: the single parameter address is documented as 'The wallet's 0x address (your identity)'. The description does not add further parameter details, but none are needed since the schema fully explains the one required input. 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?

The description opens with a precise action—'Step 1 of binding the API key you are calling with to a wallet'—and says the tool returns a SIWE message to sign. It also explicitly distinguishes itself from claim_agent_start, so an agent can immediately tell which workflow this belongs to.

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 states exactly when to use the tool: when the key came from get_key and the user wants persistence across sessions. It also lists exclusions, including claiming an agent on another key and already-bound keys, naming the alternative claim_agent_start. This is exemplary routing guidance.

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