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

Annotations only declare readOnlyHint=true, and the description adds substantial behavior beyond that: result ordering, included payload data, the four-state delivery lifecycle, the retry schedule (nextRetryAt), and the recommendation to re-poll while PENDING/DELIVERING. It does not disclose any result-size limit or pagination for a tool that claims to show 'every' delivery, which is the one meaningful gap.

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?

Front-loads what the tool returns and its ordering, then compresses state semantics into compact 'STATE = meaning' fragments. No filler sentences; each sentence conveys a distinct operational fact.

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 does the work of describing return fields (payload, receiver result, lastStatusCode, lastError, nextRetryAt) and state meanings, which is exactly what an agent needs. It stops short of stating whether the list is bounded or truncated, leaving a minor gap for a 'shows every delivery' tool.

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 coverage is 100% and the single goalId parameter is documented as coming from create_test_goal. The description reinforces the sandbox-goal scoping but adds no format or provenance detail beyond the schema, so the baseline of 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?

Names a specific verb (shows/list) plus resource (webhook deliveries) and scopes it to a sandbox goal and a defined ordering (newest first). No sibling tool covers webhook delivery history, so an agent can distinguish it from get_goal or simulate_goal_event without reading schemas.

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?

Explicitly tells the agent what to do with results ('Use lastStatusCode and lastError to debug the receiver') and what to do with in-flight states ('check again in a few seconds'), which is actionable when-to-use guidance. It also defines every terminal and pending state so the agent knows what an empty/failed result means.

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