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

Goes well beyond the annotations: discloses SSRF-safe DNS validation, that the call returns a durable operation receipt (async, not the final endpoint), and that the signing secret appears only in the completed operation result — a critical fact an agent would otherwise get wrong. It never explains why destructiveHint is true, which is the one remaining behavioral gap for a mutation tool.

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 dense sentences, front-loaded with the action and validation behavior, with the secret-delivery caveat placed last where it matters. Zero filler.

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?

Output schema exists, so return shape needn't be explained, yet the description still clarifies when the signing secret becomes available. Missing only the retrieval path for the operation receipt (e.g., get_job_status/list_operations) and the idempotencyKey contract, which would close the loop for an agent.

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 0%, so the description must carry both parameters. It effectively adds the HTTPS-only constraint on 'url' (not enforced by the schema), but says nothing about 'idempotencyKey' — no explanation that it deduplicates retries, despite idempotentHint being set. Half the parameter surface remains undefined.

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?

Specific verb + resource ('Creates an HTTPS webhook endpoint for the Wisprs webhooks API') with a scope qualifier (SSRF-safe DNS validation) that clearly separates it from list_webhook_endpoints and update_webhook_endpoint. An agent knows exactly what this does without opening the schema.

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 create semantics imply usage, but nothing states when to call this versus update_webhook_endpoint or list_webhook_endpoints, nor any prerequisite (e.g., existing endpoint conflicts, plan limits). The doc link provides an escape hatch but no in-description routing.

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