🩺 Runner Doctor UpdateRunner Doctor: 2026-07-27 scan — B13 update + two new failure modes (B15, B16)

[github-actions]

Summary

• Scan window: 2026-07-26 to 2026-07-27
• Items reviewed: 5 newly created/updated issues ([awf] agent-volumes: environment variables in sandbox.agent.mounts not expanded at runtime #6649, [awf] cli: --network-isolation conflicts with auto-enabled --enable-host-access for localhost allowlist #6651, [awf] squid-config: topologyAttach MCP gateway hostname not added to Squid ACL allowlist #6652, agent v0.27.42 image contains Go runtime affected by GO-2026-4337 #6640, [awf] api-proxy: no runtime secret-backed custom OpenAI-compatible endpoint support #6650)
• Genuinely new lessons: 3 (1 update to existing B13 + 2 new failure modes)

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Proposed knowledge-base changes

File: .github/workflows/shared/self-hosted-failure-modes.md

Update: B13 — add open sub-issue #6652 noting remaining Squid ACL gap

Current B13 row states that #6473 fully fixes the Squid ACL auto-add for topologyAttach peers. Issue #6652 (filed 2026-07-27) reports the symptom still occurs (CONNECT awmg-mcpg:8080 denied by Squid; block report incorrectly recommends adding awmgmcpg to network.allowed, which then fails schema validation). This indicates #6473's fix is incomplete or missing for the case where the hostname appears only under topologyAttach but not difcProxyHost.

Proposed change — in B13's "Fix / flag" column, append to the existing text:

Open sub-issue (#6652): topologyAttach MCP gateway hostname (awmg-mcpg) is still blocked by Squid in some configurations after #6473; the Firewall Issue Dispatcher block report incorrectly suggests adding awmgmcpg to network.allowed, which fails schema validation. Root cause under investigation.

Proposed change — in B13's "Citations" column, add github/gh-aw-firewall#6652.

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New row: B15 — --network-isolation conflicts with auto-enabled --enable-host-access for localhost allowlist

Field	Content
ID	B15
Signal	AWF startup fails with --network-isolation is not yet supported with --enable-host-access; happens when localhost is in the domain allowlist because the gh-aw compiler auto-enables --enable-host-access and also emits network.isolation: true + topologyAttach
Root cause	In src/cli.ts, --network-isolation and --enable-host-access are mutually exclusive with no overlap support. The gh-aw compiler (v0.82.x+) does not detect the conflict: it emits isolation:true + topologyAttach unconditionally while also auto-enabling --enable-host-access when localhost is in the allowlist. The compiled workflow always fails at runtime.
Fix / flag	Unresolved (#6651 open). Short-term workaround: remove localhost from the domain allowlist if topology/isolation is required; or set network.isolation: false in the AWF config if host-access is required.
Probe	awf --network-isolation --enable-host-access ... — reproduces immediately with not yet supported error; check compiler output for both flags being emitted together when localhost is in allowlist
Citations	#6651

New error-string lookup entry:

Observable	Likely mode
--network-isolation is not yet supported with --enable-host-access	B15 (compiler auto-emits both flags when localhost in allowlist + topology; root cause unresolved in #6651)

New known-unresolved entry:

• B15 / [awf] cli: --network-isolation conflicts with auto-enabled --enable-host-access for localhost allowlist #6651 — --network-isolation + --enable-host-access mutual-exclusion conflict when localhost in domain allowlist triggers auto-enable; fix requires either compiler guard or AWF relaxation

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New row: B16 — ${VAR} in sandbox.agent.mounts not shell-expanded; host path rejected

Field	Content
ID	B16
Signal	AWF rejects a --mount entry with a non-absolute host path error; the mount spec was defined as ${TERRAFORM_CLI_PATH}/terraform:... (or similar env-var pattern) but the literal string ${TERRAFORM_CLI_PATH} reaches AWF's volume validator
Root cause	The gh-aw compiler wraps sandbox.agent.mounts specs containing ${} references in single quotes in the generated shell invocation. Bash single quotes prevent variable substitution, so the literal variable reference string (e.g. ${TERRAFORM_CLI_PATH}) reaches AWF's volume validation instead of the resolved absolute path.
Fix / flag	Unresolved (#6649 open). Workaround: replace ${VAR} references with their literal values in sandbox.agent.mounts, or stage the path into a wrapper script that expands before calling AWF.
Probe	Inspect the generated awf invocation in the compiled lock file — if mount specs appear in single quotes containing ${...}, the bug is present. Running awf ... --mount '${VAR}/path:/dest' reproduces the rejection.
Citations	#6649

New error-string lookup entry:

Observable	Likely mode
AWF rejects --mount with "host path must be absolute" (or similar) and the path visibly contains ${VAR_NAME} unexpanded	B16 (single-quote wrapping by compiler prevents shell expansion of ${} in mount specs; root cause unresolved in #6649)

New known-unresolved entry:

• B16 / [awf] agent-volumes: environment variables in sandbox.agent.mounts not expanded at runtime #6649 — ${VAR} in sandbox.agent.mounts passed literally by single-quote wrapping in compiler; AWF rejects non-absolute host paths

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Proposed doctor changes

File: .github/workflows/self-hosted-runner-doctor.md

Same additions as the shared catalog:

• B13: append open sub-issue [awf] squid-config: topologyAttach MCP gateway hostname not added to Squid ACL allowlist #6652 note in Fix/Probe and Citations
• B15 table row + error-string lookup + known-unresolved entry
• B16 table row + error-string lookup + known-unresolved entry

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Proposed portable agent changes

File: .github/agents/self-hosted-runner-doctor.md

Apply the identical changes as described above for both self-hosted-failure-modes.md and self-hosted-runner-doctor.md so the portable agent's embedded catalog stays in sync.

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Source issues and PRs

• [awf] squid-config: topologyAttach MCP gateway hostname not added to Squid ACL allowlist #6652 — [awf] squid-config: topologyAttach MCP gateway hostname not added to Squid ACL allowlist (open, 2026-07-27)
• [awf] cli: --network-isolation conflicts with auto-enabled --enable-host-access for localhost allowlist #6651 — [awf] cli: --network-isolation conflicts with auto-enabled --enable-host-access for localhost allowlist (open, 2026-07-27)
• [awf] agent-volumes: environment variables in sandbox.agent.mounts not expanded at runtime #6649 — [awf] agent-volumes: environment variables in sandbox.agent.mounts not expanded at runtime (open, 2026-07-27)

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• expires on Aug 26, 2026, 7:27 PM UTC