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

Annotations cover the safety profile (destructive, idempotent, openWorld), and the description still adds substantial behavior: auth is required, enabled=true resets consecutive_failures while enabled=false halts deliveries, the returned webhook is secret-redacted, and four specific failure codes are listed. It is consistent with the destructive/idempotent annotations rather than contradicting them.

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?

The usage trigger is front-loaded, and the remaining content is dense but all informational — constraints, return shape, and error codes. It reads as a long single block rather than cleanly separated lines, but no sentence is filler, so it stays well above the padding threshold.

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 mutation tool with no output schema, the description covers everything an agent needs: required vs optional inputs, auth requirement, the semantic effect of each toggle, the redacted return, and the enumerable failure modes. Nothing material is left to be discovered from an error at call time.

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 the baseline is 3; the description's parameter notes (enabled resets consecutive_failures, inbox_ids capped at 10, url is http(s)) largely restate what the schema already documents. It adds no format or syntax detail beyond the schema, so it earns no premium here.

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 names the exact resource (webhook) and the exact facets that can change (URL, event list, inbox filter, enabled flag), which is a specific verb+resource statement. That field-level scope cleanly separates it from cooper_register_webhook, cooper_delete_webhook, cooper_rotate_webhook_secret, and cooper_test_webhook without needing to open a 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?

"Use this when a webhook URL, event list, inbox filter, or enabled flag should change" gives an explicit trigger condition, which is clear usage context. It stops short of a 5 because it names no alternatives or exclusions (e.g. create via cooper_register_webhook, secret rotation via cooper_rotate_webhook_secret), leaving that routing to inference.

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