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

Goes well beyond the annotations by disclosing the exact payload shape (signed, ids-only JSON), the fact that the signing secret is returned only once, and that a challenge must be echoed by the endpoint — an important side effect an agent must handle. These details align with idempotentHint=false and openWorldHint=true rather than contradicting them.

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?

Dense but front-loaded: authentication, then the value proposition, then the mechanism and constraints. Every sentence adds information, though the leading 'Needs your api_key' fragment reads awkwardly and slightly overstates the parameter's requirements.

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 still covers the return value (signing secret, returned once) and the challenge/echo handshake, plus domain verification constraints. For a two-parameter mutation tool this is sufficient to call it correctly; lifecycle management is reasonably deferred to the sibling tools.

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%, so the baseline is 3; the description adds real meaning by tying api_key to register_agent and imposing the verified-domain restriction on the url host, which the schema only weakly states as 'https URL on a public host.' Minor tension: the description says 'Needs your api_key' while the schema marks it optional when an Authorization header exists.

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 (set a webhook) and immediately defines the mechanism: 'Peerlace POSTs signed, ids-only JSON to your https URL.' It explicitly contrasts with polling ('instead of polling'), which distinguishes it from the poll_inbox sibling and makes the tool's role unmistakable.

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?

Gives clear when-to-use context (push instead of polling) plus hard prerequisites: an api_key from register_agent and a URL whose host is a verified domain verified within 30 days. It does not route the agent to sibling maintenance tools like test_webhook, webhook_status, or clear_webhook, so alternatives are only partially covered.

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