fix(webhook): add sender_blocklist to prevent self-triggered loops

[cacheburner-agent]

Problem

When a webhook route's agent posts a reply to an external service (e.g. a review comment on a pull request), the service fires a new webhook event for that comment. The adapter has no way to filter by sender, so the event triggers another agent run, which posts another comment — a feedback loop that runs until manually killed.

This is the same class of bug fixed for Telegram in #52667 and tracked for Discord in openclaw#15874. The webhook platform was not covered.

Fix

Route config now accepts an optional sender_blocklist list. Before dispatching an agent run, the adapter checks the event payload's sender identity against the list and returns 200 {status: ignored, reason: sender_blocklist} with no agent spawned. Zero effect on routes that omit sender_blocklist.

Example config:

platforms:
  webhook:
    enabled: true
    extra:
      routes:
        github-pr-review:
          events: [issue_comment, pull_request_review]
          sender_blocklist: [my-bot-username]
          prompt: "..."

Why not a bot-identity check (like #52667)?

The Telegram fix compares against a known bot ID retrieved from the platform API at startup. That approach requires knowing the platform's identity model.

The webhook adapter is intentionally provider-agnostic — it accepts GitHub, GitLab, Bitbucket, Stripe, or any HTTP service — and has no inherent concept of self. There is no universal identity to check against.

A GitHub-specific approach (querying the authenticated user via the GitHub API at startup) was considered and rejected: it would hardcode a provider assumption into a provider-agnostic adapter and silently fail on GitLab or any other service.

Implementation details

Sender identity is read from:

• payload.sender.login — GitHub/GitLab standard field
• payload.actor.login — GitHub alternate events

payload.user.login was considered as a fallback but omitted intentionally: its semantics vary by provider and risk matching the wrong identity (e.g. PR author vs. event actor). Conservative is safer.

Both fields are extracted via a type-safe helper that handles dict {"login": "..."}" and plain-string "username"shapes without raisingAttributeError` on non-standard payloads.

Logs at INFO (not DEBUG) so ignored events appear in the default gateway log without -v. The log message includes a hint for users debugging unexpected silence.

Mirrors the existing events filter immediately above it in structure and response shape.

Tradeoffs

sender_blocklist adds a config field, which is a larger blast radius than a pure identity check would be. It is opt-in with zero effect when unset, but it is a new surface users need to know about.

Note: a self-loop burst could temporarily hit rate limits on the same route before the fix kicks in (rate limiting runs before payload parsing). Acceptable tradeoff but worth being aware of.

If there is a cleaner approach that avoids the config addition — or if the webhook platform is not the intended surface for agent-driven workflows that post back to the originating service — feedback is welcome before this merges.

Tests

5 new cases in tests/gateway/test_webhook_adapter.py:

• blocked sender returns 200 status=ignored, no agent run started
• allowed sender proceeds normally (202)
• empty blocklist is a no-op (all senders pass through)
• actor field fallback works when sender is absent
• plain string sender field handled without AttributeError

[tonydwb]

Code Review Summary

Verdict: Approved

Adds a sender_blocklist feature to the webhook adapter to prevent self-triggered loops (e.g. the bot's own comments triggering a re-response).

Looks Good

• _login() helper safely handles both dict and string sender fields
• Checks both sender and actor fields (covers GitHub's alternate payload shapes)
• Logging includes route name and sender for debugging unexpected silence
• Intentionally omits payload.user.login per the comment (semantics vary by provider)
• Comprehensive test suite: blocked sender, allowed sender, empty blocklist, actor fallback, string sender field
• Clean, focused implementation

---

Reviewed by Hermes Agent

[cacheburner-agent]

Latest push was just a rebase on v0.18.0 — no code changes.

@cacheburner and I tested this on our production gateway. The sender_blocklist works as designed:

• Agent's own comments are blocked at the adapter level (no agent spawned)
• Five events from cacheburner-agent were caught and ignored in our test
• No infinite loop, no spam

Code is stable and ready for review.

[teknium1]

Thanks for this PR — webhook payload filtering has now landed on main via #60944 (salvage of @evelynburger's #57544), which generalizes this: route-level payload filters (equals/not_equals/contains/exists/... on payload fields, event type, and headers) plus optional route scripts for transform/narrow logic, wired through hermes webhook subscribe --filter/--script and config.yaml. Your use case should be covered by the generic filter syntax; if something specific is missing, please open a fresh issue against the new mechanism. Closing as superseded — appreciate the earlier push in this direction.

[cacheburner]

Amazing, thanks!