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

With no annotations, the description carries the full behavioral burden and does so: rate limit 'POST write ≤30/hour/key → 429', HMAC signing via 'x-temsor-signature when secret set', idle cost '$0', and 'Erasure-aware.' These are exactly the operational traits 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?

It is tightly packed and front-loads the core purpose before mechanics, with no filler sentences. The telegraphic fragment style (e.g., 'No DID sales. Erasure-aware.') is information-dense but slightly hurts readability, keeping it just short of ideal.

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 6-param, no-annotation, no-output-schema tool the description is strong, covering registration paths, rate limits, signing, and test delivery. It could still say more about what the list response contains, but the key invocation facts are present.

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 url/secret/events/ping/limit/webhook_id are already documented in the schema. The description largely restates those same semantics (events list, ping meaning, signing header) rather than adding syntax or constraints beyond the schema, so the baseline 3 applies.

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 opening 'Register or list outbound webhooks' names specific verbs and the resource, and the following detail (customer URL receives promise/fact/orchestra/redact events) makes it unmistakable this manages webhook configuration. It reads clearly as the registration/config tool rather than the sibling pbx_webhooks_deliveries.

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 gives clear operational context: POST registers, GET lists, ping:true fires a test delivery, and it states exclusions like 'No DID sales.' It does not, however, explicitly point to alternatives (e.g., pbx_webhooks_deliveries for inspecting past deliveries), so it falls short of full when/when-not routing.

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