PR #28255: feat(integrations): AgentCOGS per-customer margin callback

• Repository: BerriAI/litellm
• Author: vaibhav11123
• State: open | merged: False
• Link: https://github.com/BerriAI/litellm/pull/28255

Description (problem / solution / changelog)

Summary

Adds AgentCOGS as a community billing callback (Lago / OpenMeter pattern) for B2B SaaS teams using LiteLLM who need per-customer LLM cost and gross margin tracking.

Closes / relates to #28254

Changes

• litellm/integrations/agentcogs.py — AgentCOGSLogger → POST /v1/ingest
• Registry + _custom_logger_compatible_callbacks_literal: agentcogs
• tests/test_litellm/integrations/test_agentcogs.py — payload, idempotency, proxy attribution, non-blocking errors

Docs: Per repo policy, documentation is not in this PR. A draft for BerriAI/litellm-docs is maintained at https://github.com/vaibhav11123/agentcogs/blob/main/docs/internal/litellm-docs-agentcogs.md (separate docs PR to follow).

Usage

litellm.success_callback = ["agentcogs"]
litellm.completion(..., user="your_customer_id")

litellm_settings:
  callbacks: ["agentcogs"]

Env: AGENTCOGS_API_KEY, AGENTCOGS_WORKSPACE_ID, optional AGENTCOGS_ENDPOINT, optional AGENTCOGS_CHARGE_BY (end_user_id | user_id | team_id).

Review feedback addressed

• Removed in-repo docs/my-website/docs/observability/agentcogs.md (litellm-docs repo)
• run_id uses litellm_call_id for idempotent ingest dedup
• Proxy attribution mirrors Lago (AGENTCOGS_CHARGE_BY); client metadata.agentcogs_customer_id ignored on proxy requests
• HTTP errors logged at warning (not swallowed at debug-only)

Testing

pytest tests/test_litellm/integrations/test_agentcogs.py -q

Notes

• Complements Lago/OpenMeter (usage billing) with per-customer margin (cost + revenue join).
• Parallel user-landed path: https://github.com/vaibhav11123/agentcogs/blob/main/docs/integrations/litellm.md

Changed files

• litellm/__init__.py (modified, +1/-0)
• litellm/integrations/agentcogs.py (added, +237/-0)
• litellm/litellm_core_utils/custom_logger_registry.py (modified, +2/-0)
• tests/test_litellm/integrations/test_agentcogs.py (added, +199/-0)