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

Adds real context beyond the annotations: the signing secret is returned exactly once and must be relayed to the user, and the operation is free. That 'returned once' warning is the critical operational detail an agent would otherwise miss. It does not address duplicate-URL behavior or verification/retry flow, keeping it from a 5.

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?

Three short sentences, zero filler, with the core action front-loaded and the agent-critical instruction ('relay it to the user') placed immediately after. Nothing is redundant with the title or annotations.

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 5-parameter mutation with no output schema, the description covers the action, the one-time secret return, and the cost. Remaining gaps (what happens on duplicate registration, whether the URL is verified before events flow) are modest but real for a non-idempotent create.

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 80%, so the schema already documents url, batch_max, event_types and include_contacts. The description adds no parameter-level meaning beyond the https constraint already in the schema, so the baseline of 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 ('Registers an https URL to receive prospect and list events'), which is unambiguous and clearly distinct from the read-only sibling dealmachine_webhook_list. It stops short of explicitly naming the sibling as an alternative, so it is clear but not fully differentiated in-text.

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?

The use case is implied by the description (you register a URL to receive events), but there is no explicit guidance on when to call this versus dealmachine_webhook_list, no prerequisites beyond the https constraint, and no note on whether re-registering the same URL is allowed or creates a duplicate.

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