Greptile Summary

This PR introduces server-side conversation reconstruction from previous_response_id so that Hadrian — not the upstream provider — is the system of record for chaining. It also adds strip_gateway_fields() to prevent orchestration-only fields (store, background, models, provider, plugins, sovereignty_requirements, skills) from leaking to upstream providers, and adds echo-field restoration so the persisted response and every streamed lifecycle event carry the caller's intent (Hadrian resp_… id, original store, original previous_response_id).

• responses_chain.rs (new): walks the previous_response_id linked list, replays turns oldest→newest, hard-errors on corrupt records (addressing the silent-drop bug noted in the previous review).
• response_persister.rs: new ResponseEchoFields struct threaded into the streaming wrapper; rewrite_lifecycle_echo_fields rewrites only lifecycle events (delta events short-circuit on a cheap byte-scan before JSON parsing).
• chat.rs / background_executor.rs: stash original_previous_response_id before reconstruction clears payload.previous_response_id, and use the stashed value for both container-hint lookups and echo — fixing the previously reported container-binding bugs.

Confidence Score: 5/5

Safe to merge — the two container-binding breakages from the prior review are both fixed, and the new chain reconstruction, gateway-field stripping, and echo-field restoration are well-tested and logically sound.

The reconstruction logic hard-errors on corrupt records rather than silently dropping turns, the original_previous_response_id stash is applied consistently in all four lookup sites, and strip_gateway_fields is backed by a unit test. No new defects were found.

No files require special attention. The most complex new code (responses_chain.rs and the echo-field rewrite path in response_persister.rs) is well-covered by unit tests.

Important Files Changed

Sequence Diagram

sequenceDiagram
    participant Client
    participant ChatRoute as chat.rs
    participant Chain as responses_chain.rs
    participant Store as ResponsesStore
    participant Provider as Upstream Provider
    participant Persister as response_persister.rs

    Client->>ChatRoute: "POST /responses {previous_response_id, input}"
    Note over ChatRoute: Stash original_previous_response_id & original_input
    ChatRoute->>Chain: reconstruct_input(store, org_id, prev_id, current_input)
    loop Walk chain newest to oldest
        Chain->>Store: get(id, org_id)
        Store-->>Chain: ResponseRecord
    end
    Chain-->>ChatRoute: "Vec<ResponsesInputItem> (full transcript)"
    Note over ChatRoute: payload.input = reconstructed, payload.previous_response_id = None
    ChatRoute->>Provider: POST /responses (strip_gateway_fields applied)
    alt Streaming
        Provider-->>Persister: SSE events
        Note over Persister: rewrite_lifecycle_echo_fields: id, store, previous_response_id restored
        Persister-->>Client: SSE events (echo fields restored)
        Persister->>Store: Persist final state
    else Non-streaming
        Provider-->>ChatRoute: JSON body
        Note over ChatRoute: apply_response_echo_fields patches id, store, previous_response_id
        ChatRoute-->>Client: JSON body (echo fields restored)
        ChatRoute->>Store: Persist with original_input + original_previous_response_id
    end

_{Reviews (6): Last reviewed commit: "Review fixes" | Re-trigger Greptile}

@greptile-apps

@greptile-apps