From bc6a3436ace205116c68f34fd01c6b49728afb09 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 20 Aug 2026 18:08:22 +0000
Subject: [PATCH] docs: document run-id forwarding to api-proxy sidecar

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 docs/api-proxy-sidecar.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/api-proxy-sidecar.md b/docs/api-proxy-sidecar.md
index 050388b17..6e5e28ff3 100644
--- a/docs/api-proxy-sidecar.md
+++ b/docs/api-proxy-sidecar.md
@@ -149,6 +149,8 @@ The API proxy sidecar receives **real credentials** and routing configuration:
 | `COPILOT_PROVIDER_BASE_URL` | Real upstream URL | env set on host | User-supplied upstream URL for direct-BYOK mode; sidecar forwards Copilot CLI requests there instead of `api.githubcopilot.com`. |
 | `GEMINI_API_KEY` | Real API key | env set on host | Google Gemini API key (injected into requests) |
 | `GOOGLE_API_KEY` | Real API key | env set on host | Google Vertex AI API key (injected into `x-goog-api-key` header) |
+| `GITHUB_RUN_ID` | Forwarded GitHub Actions value | `GITHUB_RUN_ID` set on host (GitHub Actions runs) | Combined with `GITHUB_RUN_ATTEMPT` to derive a stable per-run `X-Interaction-Id` for Copilot API requests (CAPI prompt-cache key); see [Prompt-cache and attribution headers](./auth-matrix.md#prompt-cache-and-attribution-headers-githubcopilotcom-only) in the auth matrix. |
+| `GITHUB_RUN_ATTEMPT` | Forwarded GitHub Actions value | `GITHUB_RUN_ATTEMPT` set on host (GitHub Actions runs) | Paired with `GITHUB_RUN_ID` for the `X-Interaction-Id` derivation above; defaults to `1` if unset. |
 | `HTTP_PROXY` | `http://172.30.0.10:3128` | Always | Routes through Squid; sidecar traffic is exempt from domain ACLs |
 | `HTTPS_PROXY` | `http://172.30.0.10:3128` | Always | Routes through Squid; sidecar traffic is exempt from domain ACLs |