fix(spec+compiler): update MCP gateway OTLP headers to string-only (v1.13.0) by Copilot · Pull Request #25135 · github/gh-aw

Copilot · 2026-04-07T17:32:35Z

Summary

Updates the MCP Gateway Specification, JSON schemas, and compiler so that the headers field in the opentelemetry configuration is exclusively a string, removing the previously supported object form. The compiler no longer converts the headers string to a JSON object — the raw string value is passed through directly. The MCP Gateway version has been bumped to v0.2.17, which includes the updated schema that accepts string headers.

Changes

Specification (`docs/src/content/docs/reference/mcp-gateway.md`)

Bumped version: 1.12.0 → 1.13.0
Section 4.1.3.6: Changed headers type from object | string to string; updated description to clarify the value is passed through as-is
Removed dual-form configuration examples; replaced with a single string-form example
Removed Section 4.1.3.6.1 (Headers String Format) — no parsing rules needed since the string is passed through unchanged
Updated requirements: added headers MUST be a string when provided; removed string-parsing requirement
Updated compliance test range: T-OTEL-001 through T-OTEL-012 → T-OTEL-001 through T-OTEL-010
Updated T-OTEL-006: changed from "object form headers sent" to "string headers passed through as-is"
Removed T-OTEL-011 and T-OTEL-012 (string-form parsing tests)
Updated Appendix A.6 and A.7: replaced object-form headers with string form
Added change log entry for v1.13.0

JSON Schemas

pkg/workflow/schemas/mcp-gateway-config.schema.json
docs/public/schemas/mcp-gateway-config.schema.json

Both: changed opentelemetryConfig.headers from oneOf [object, string] to plain string type with updated description.

Compiler (`pkg/workflow/mcp_renderer.go`)

Removed the Node.js bash preamble that converted OTEL_EXPORTER_OTLP_HEADERS from key=value,... format into a JSON object (_GH_AW_OTLP_HEADERS_JSON)
Gateway config now emits "headers": "${OTEL_EXPORTER_OTLP_HEADERS}" — a JSON string value that bash expands at runtime — instead of the previously injected JSON object

Gateway Version (`pkg/constants/version_constants.go`)

Bumped DefaultMCPGatewayVersion: v0.2.16 → v0.2.17
v0.2.16 had a bundled schema requiring headers to be an object, causing startup validation failures with the new string-form output; v0.2.17 accepts string headers

Workflow Lock Files

All 182 workflow lock files recompiled to reflect the updated compiler output and gateway version

Changeset

Type: minor
Description: Updated MCP gateway OpenTelemetry headers to string-only and removed object-form support in spec, schema, and compiler output. Bumped gateway image to v0.2.17.

Generated by Changeset Generator for issue #25135 · ◷

Agent-Logs-Url: https://github.com/github/gh-aw/sessions/3996a176-e590-4a9b-a928-05c51894409e Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-04-07T17:45:32Z

@lpcox FYI

pelikhan · 2026-04-07T17:46:08Z

@copilot update compiler to emit string with headers value and NOT try to parse them to a JSON object.

…sion Agent-Logs-Url: https://github.com/github/gh-aw/sessions/6920f518-5ec9-4aa2-b777-42c0b5b9c02d Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-04-07T17:56:53Z

@copilot update compiler to emit string with headers value and NOT try to parse them to a JSON object.

Done in commit 58c4131. The compiler (mcp_renderer.go) no longer converts the headers string to a JSON object. The bash preamble with the Node.js JSON.stringify conversion has been removed, and the gateway config now emits "headers": "${OTEL_EXPORTER_OTLP_HEADERS}" — a plain JSON string that bash expands at runtime from the job-level env var. All 182 workflow lock files have been recompiled to reflect the change.

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https://api.github.com/repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b
- Triggering command: /usr/bin/gh gh api /repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b --jq .object.sha (http block)
https://api.github.com/repos/github/gh-aw
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pelikhan · 2026-04-07T20:31:15Z

@copilot merge main and recompile

…teway-specification Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-04-07T20:37:21Z

@copilot merge main and recompile

Done in commit c537fa3. Merged main and recompiled all 182 workflows.

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I tried to connect to the following addresses, but was blocked by firewall rules:

https://api.github.com/graphql
- Triggering command: /usr/bin/gh /usr/bin/gh api graphql -f query=query($owner: String!, $name: String!) { repository(owner: $owner, name: $name) { hasDiscussionsEnabled } } -f owner=github -f name=gh-aw (http block)
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https://api.github.com/repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b
- Triggering command: /usr/bin/gh gh api /repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b --jq .object.sha (http block)
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https://api.github.com/repos/githubnext/agentics/git/ref/tags/-
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If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
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github-actions · 2026-04-07T21:01:22Z

🌑 The shadows whisper... Smoke Codex failed. The oracle requires further meditation...

github-actions · 2026-04-07T21:01:28Z

💫 TO BE CONTINUED... Smoke Claude failed! Our hero faces unexpected challenges...

github-actions · 2026-04-07T21:01:28Z

📰 BREAKING: Smoke Copilot is now investigating this pull request. Sources say the story is developing...

github-actions · 2026-04-07T21:01:36Z

❌ Tool validation failed! Agent Container Smoke Test detected missing tools: failed

github-actions · 2026-04-07T21:03:57Z

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github-actions · 2026-04-07T21:06:51Z

Commit pushed: f4c1e24

Generated by Changeset Generator

pelikhan · 2026-04-07T21:39:25Z

@copilot recompile

Copilot · 2026-04-07T21:43:46Z

@copilot recompile

All 182 workflows are already up to date — recompile produced no changes. The lock files are current as of the previous merge commit (c537fa3).

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

https://api.github.com/graphql
- Triggering command: /usr/bin/gh /usr/bin/gh api graphql -f query=query($owner: String!, $name: String!) { repository(owner: $owner, name: $name) { hasDiscussionsEnabled } } -f owner=github -f name=gh-aw (http block)
https://api.github.com/repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b
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If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

pelikhan · 2026-04-07T22:01:06Z

@copilot Investigate https://github.com/github/gh-aw/actions/runs/24104184648/job/70323242422#step:33:1

Copilot · 2026-04-07T22:07:07Z

@copilot Investigate https://github.com/github/gh-aw/actions/runs/24104184648/job/70323242422#step:33:1

The CI failure at step 33 is a schema validation error in the MCP Gateway (v0.2.16):

Location: /gateway/opentelemetry/headers
Error: expected object, but got string
Schema location: /properties/gateway/$ref/properties/opentelemetry/properties/headers/type

The gateway (v0.2.16) has a bundled schema that expects headers to be an object, but our compiler change now emits it as a string (e.g., "headers": "${OTEL_EXPORTER_OTLP_HEADERS}"). The gateway validates the generated config against its bundled schema at startup and rejects the string form.

This is a forward-compatibility issue: our spec v1.13.0 changes headers to string-only, but gateway v0.2.16 was built with the old schema that required an object. The gateway binary needs to be updated (v0.2.17+) to accept string headers before this PR can be safely deployed.

pelikhan · 2026-04-07T22:18:27Z

@copilot Update the Gateway version and recompile

Agent-Logs-Url: https://github.com/github/gh-aw/sessions/e966cd52-1b64-4d0a-b619-2b716bc3f6db Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-04-07T22:24:08Z

@copilot Update the Gateway version and recompile

Done in commit b39e7b8. Bumped DefaultMCPGatewayVersion from v0.2.16 to v0.2.17 in pkg/constants/version_constants.go and recompiled all 182 workflows. The new gateway version should include the updated schema that accepts string headers.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

https://api.github.com/graphql
- Triggering command: /usr/bin/gh /usr/bin/gh api graphql -f query=query($owner: String!, $name: String!) { repository(owner: $owner, name: $name) { hasDiscussionsEnabled } } -f owner=github -f name=gh-aw (http block)
https://api.github.com/repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b
- Triggering command: /usr/bin/gh gh api /repos/astral-sh/setup-uv/git/ref/tags/eac588ad8def6316056a12d4907a9d4d84ff7a3b --jq .object.sha (http block)
https://api.github.com/repos/github/gh-aw
- Triggering command: /usr/bin/gh gh api /repos/github/gh-aw --jq .visibility (http block)
https://api.github.com/repos/githubnext/agentics/git/ref/tags/-
- Triggering command: /usr/bin/gh gh api /repos/githubnext/agentics/git/ref/tags/- --jq .object.sha (http block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

github-actions · 2026-04-07T22:29:48Z

❌ Tool validation failed! Agent Container Smoke Test detected missing tools: failed

github-actions · 2026-04-07T22:29:48Z

📰 BREAKING: Smoke Copilot is now investigating this pull request. Sources say the story is developing...

github-actions · 2026-04-07T22:29:49Z

🌑 The shadows whisper... Smoke Codex failed. The oracle requires further meditation...

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github-actions · 2026-04-07T22:32:16Z

📰 DEVELOPING STORY: Smoke Copilot reports failed. Our correspondents are investigating the incident...

github-actions · 2026-04-08T13:25:25Z

Hey @Copilot 👋 — great work on the MCP Gateway OTLP headers refactor! Simplifying from the dual object/string form down to a pure string pass-through is a clean improvement, and the spec, schema, compiler, and 182 lock files all look consistent.

One gap to address before this moves out of draft:

Missing test coverage — pkg/workflow/mcp_renderer.go was modified (the headers output line changed from \$\{_GH_AW_OTLP_HEADERS_JSON} with an object shape to "\$\{OTEL_EXPORTER_OTLP_HEADERS}" as a JSON string), but pkg/workflow/engine_helpers_shared_test.go — which already covers RenderJSONMCPConfig — was not updated. A test asserting the new string-form headers output (and confirming the old bash preamble is gone) would close this gap and prevent regressions.

If you'd like a hand, you can assign this prompt to your coding agent:

Add test coverage for the updated OTLP headers behaviour in pkg/workflow/mcp_renderer.go.

Context:
- The PR changed headers output from a bash-preamble-converted JSON object (`\$\{_GH_AW_OTLP_HEADERS_JSON}`) to a plain JSON string (`"\$\{OTEL_EXPORTER_OTLP_HEADERS}"`).
- The bash preamble that converted OTEL_EXPORTER_OTLP_HEADERS from key=value,... format into a JSON object was removed.
- Existing tests live in pkg/workflow/engine_helpers_shared_test.go and already call RenderJSONMCPConfig.

Tasks:
1. In pkg/workflow/engine_helpers_shared_test.go, add or update a test case that:
   a. Calls RenderJSONMCPConfig with a non-empty OTLPEndpoint and OTLPHeaders value.
   b. Asserts the rendered output contains `"headers": "\$\{OTEL_EXPORTER_OTLP_HEADERS}"` (string form).
   c. Asserts the rendered output does NOT contain `_GH_AW_OTLP_HEADERS_JSON` (old object form).
   d. Asserts no bash preamble converting key=value headers is present in the YAML output.
2. Run `make test` (or `go test ./pkg/workflow/...`) to confirm all tests pass.
3. Run `make agent-finish` to validate the full build before marking the PR ready for review.

Generated by Contribution Check · ● 2M · ◷

fix(spec): update MCP gateway spec OTLP headers to string-only

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Agent-Logs-Url: https://github.com/github/gh-aw/sessions/3996a176-e590-4a9b-a928-05c51894409e Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI assigned Copilot and pelikhan Apr 7, 2026

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fix(compiler): emit OTLP headers as string, remove JSON object conver…

58c4131

…sion Agent-Logs-Url: https://github.com/github/gh-aw/sessions/6920f518-5ec9-4aa2-b777-42c0b5b9c02d Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~fix(spec): update MCP gateway OTLP headers to string-only (v1.13.0)~~ fix(spec+compiler): update MCP gateway OTLP headers to string-only (v1.13.0) Apr 7, 2026

Copilot finished work on behalf of pelikhan April 7, 2026 17:57

lpcox mentioned this pull request Apr 7, 2026

Update gateway to accept OTLP headers as string (spec v1.13.0) github/gh-aw-mcpg#3337

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Copilot AI mentioned this pull request Apr 7, 2026

Update OTLP headers to accept string format (spec v1.13.0) github/gh-aw-mcpg#3338

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[aw] No-Op Runs #25141

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Copilot started work on behalf of pelikhan April 7, 2026 20:31 View session

Merge remote-tracking branch 'origin/main' into copilot/update-mcp-ga…

c537fa3

…teway-specification Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot stopped work on behalf of pelikhan due to an error April 7, 2026 20:38
The "Setup uv" custom setup step from your .github/workflows/copilot-setup-steps.yml file failed.

Merge branch 'main' into copilot/update-mcp-gateway-specification

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Copilot started work on behalf of pelikhan April 7, 2026 22:18 View session

bump: MCP Gateway version to v0.2.17 and recompile workflows

b39e7b8

Agent-Logs-Url: https://github.com/github/gh-aw/sessions/e966cd52-1b64-4d0a-b619-2b716bc3f6db Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

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pelikhan mentioned this pull request Apr 7, 2026

Support for Otel headers as string (not object) github/gh-aw-mcpg#3350

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Copilot AI mentioned this pull request Apr 8, 2026

No-op: Otel headers as string already addressed by #3338 github/gh-aw-mcpg#3353

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[PR Triage Report] PR Triage Report - 2026-04-08 #25296

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Summary

Changes

Specification (docs/src/content/docs/reference/mcp-gateway.md)

JSON Schemas

Compiler (pkg/workflow/mcp_renderer.go)

Gateway Version (pkg/constants/version_constants.go)

Workflow Lock Files

Changeset

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Specification (`docs/src/content/docs/reference/mcp-gateway.md`)

Compiler (`pkg/workflow/mcp_renderer.go`)

Gateway Version (`pkg/constants/version_constants.go`)

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