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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds real value on top: the required key scope (sites:read) and the explicit data boundary "Never the signing secret." That secret-exclusion note is exactly the kind of behavioral fact an agent cannot infer from structured fields. Minor gap: "latest deliveries" doesn't say how many or whether they're truncated.

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 sentences, front-loaded with the safety statement and then the payload shape, with zero filler. The relationship to webhooks_list is placed early where it aids selection.

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 2-param read tool with no output schema, the description covers the return shape (masked URL, targets, events, deliveries), the auth scope, and the secret exclusion — enough to call it correctly. It doesn't address not-found behavior or delivery pagination, which is the only remaining gap.

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% and both parameters are documented in-schema (id comes "from webhooks_list", site is the list_sites id), so the schema does the heavy lifting. The description adds no syntax or format detail beyond that, making the baseline 3 correct.

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?

"One form Webhook ... the masked URL, target forms, events and the latest deliveries" makes it clear this retrieves a single webhook record and names its fields, and it explicitly frames itself as the singular counterpart to webhooks_list. The verb is implicit rather than stated, so it falls just short of a 5.

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 description implies read-only retrieval and positions itself relative to webhooks_list ("the same shape as"), which gives an agent a usable routing cue. But it never states when to use this instead of webhooks_test or webhooks_update, and there is no explicit exclusion or precondition beyond the scope note.

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