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

Annotations already declare readOnlyHint and idempotentHint, and the description goes beyond them with real disclosure: addresses are truncated to host only, signing secrets are never returned, and it explains why (the full address is a key for automation services). That is meaningful output-behavior context an agent cannot get from the schema. It stops short of describing result ordering, counts, or behavior when no webhooks exist.

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 tight sentences with no filler, and the redaction caveat plus the site-wide/form-level clarification both earn their place. The one structural weakness is that it opens with a noun phrase describing the payload rather than a verb-led statement of what the call does.

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 carries the return-value explanation and does so well, naming the exposed fields and the two that are deliberately hidden. For a two-parameter read-only list tool with full annotation coverage, this is close to sufficient; only empty-result and ordering behavior are unstated.

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 site_id ('from list_sites') and the optional user_goal are already documented in the schema. The description adds nothing about either parameter, not even confirming that site_id selects which site's webhooks are enumerated. Baseline 3 is appropriate when the schema carries the parameter burden.

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 enumerates exactly what comes back ('each one's id, name, which events it fires on, whether it is on, and the host it sends to') and sharply scopes it to site-wide webhooks versus a single form's webhook. It never states the verb 'list' explicitly, and it does not distinguish itself from get_webhook or test_webhook by name, so an agent must infer the list semantics from the tool name.

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 form-level-versus-site-wide distinction is genuinely useful scoping ('a single form's own webhook is set in that form's settings'), implying this tool is for the site-level view. But there is no explicit when-to-use instruction and no reference to the obvious alternatives (get_webhook for one webhook, test_webhook for firing it, create_webhook for adding one), so routing still requires inference.

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