list_webhooksList webhook endpoints for this account.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Page size (1–100) | |
| cursor | No | Opaque cursor for the next page |
| Name | Required | Description | Default |
|---|---|---|---|
| has_more | No | True when another page of results is available | |
| webhooks | Yes | Webhook endpoints on this page | |
| next_cursor | No | Cursor to pass as `cursor` to fetch the next page; null on the last page |
Changes observed during successful MCP inspections.
Output schema / properties / webhooks / items / properties / mailboxesAdded value: +{
+ "description": "Present only when the endpoint receives mailbox events for some mailboxes only: their ids (mbx_…)",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+}Output schema / properties / webhooks / items / properties / healthAdded value: +{
+ "description": "Delivery health: last_24h (total, delivered, failed, median_latency_ms), last_delivery_at, last_status, last_response_status, and failing (a delivery failed all 5 attempts in the last 24 hours)",
+ "type": "object"
+}Output schema / properties / webhooks / items / properties / tenantsAdded value: +{
+ "description": "Present only when the endpoint receives email events for some tenants only: their external ids",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety and idempotency profile is fully covered without the description. The description's only added behavioral signal is the account-level scope, which is useful given the tenant-oriented siblings but thin; it says nothing about result ordering or whether disabled endpoints are included.
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?
A single front-loaded sentence with no wasted words, which suits a simple list operation. It is arguably too terse for the sibling landscape, but nothing is redundant or buried.
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?
An output schema exists and the annotations carry the safety profile, so the description need not explain return values or side effects. However, with a close sibling in list_webhook_deliveries, one routing sentence would have made the definition complete for an agent choosing between the two.
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 (limit as page size 1-100, cursor as an opaque next-page token) are fully documented in the schema. The description adds no meaning beyond that, 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?
States a specific verb and resource ("List webhook endpoints") plus a scope ("for this account"), which separates it from create_webhook and delete_webhook by implication. It stops short of explicitly distinguishing it from list_webhook_deliveries, which is the closest sibling and the one most likely to be confused with it.
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?
There is no when-to-use or when-not-to-use guidance and no mention of the obvious alternative, list_webhook_deliveries, which returns delivery attempts rather than endpoint definitions. The only contextual cue is the phrase "for this account," which hints at account-level scope but is not framed as a selection rule.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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