fix: web-fetch MCP server generates container format instead of command/args by Copilot · Pull Request #17822 · github/gh-aw

Copilot · 2026-02-23T03:13:19Z

tools: web-fetch was compiling to a command/args Docker exec shape that fails MCP Gateway schema validation (missing properties: 'container', additionalProperties 'command', 'args' not allowed). Affected engines: gemini, codex.

Changes

pkg/workflow/fetch.go — renderMCPFetchServerConfig now emits the gateway-compliant container key instead of command/args:
```
// Before (invalid)
"web-fetch": { "command": "docker", "args": ["run", "-i", "--rm", "mcp/fetch"] }

// After (valid)
"web-fetch": { "container": "mcp/fetch" }
```
TOML output (Codex) similarly changes from command = "docker" + args to container = "mcp/fetch".
pkg/workflow/fetch_test.go / fetch_integration_test.go — Updated assertions to match the new container shape.
smoke-codex.md — Added web-fetch: to the tools section and a new "Web Fetch Testing" step to exercise the MCP server.
smoke-gemini.md — Added web-fetch: to the tools section and a new "Web Fetch Testing" step to exercise the MCP server.
smoke-copilot.md — Already had web-fetch: in the tools section; added a "Web Fetch Testing" step to exercise it.

All three smoke test lock files now emit "container": "mcp/fetch" in the generated MCP server config.

Original prompt

This section details on the original issue you should resolve

<issue_title>tools.web-fetch compiles to invalid MCP Gateway config (command/args instead of container)</issue_title>
<issue_description>tools: web-fetch currently compiles to an MCP Gateway config that fails schema validation.

Repro

Minimal workflow:
---
name: "Web Fetch Repro"
on:
  workflow_dispatch:
engine:
  id: gemini
  model: gemini-3-pro-preview
permissions:
  contents: read
tools:
  web-fetch:
strict: false
---
Compile:
gh aw compile web-fetch-repro
Actual generated lock output

Generated .lock.yml contains:
"web-fetch": {
  "command": "docker",
  "args": ["run", "-i", "--rm", "mcp/fetch"]
}
Expected

web-fetch should be rendered in a gateway-schema-compliant server shape (stdio server with container, e.g.):
"web-fetch": {
  "container": "mcp/fetch"
}
Failure symptom

Gateway startup fails with schema errors like:

missing properties: 'container'

additionalProperties 'command', 'args' not allowed

location: /mcpServers/web-fetch

Engine impact

Affected: gemini, likely codex (both rely on MCP web-fetch server generation when tools: web-fetch is requested)

Not affected by this specific path: claude, copilot (both have built-in web-fetch support and generally skip MCP web-fetch server generation)</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes tools.web-fetch compiles to invalid MCP Gateway config (command/args instead of container) #17820

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.

✨ PR Review Safe Output Test - Run 22292196576

💥 [THE END] — Illustrated by Smoke Claude

Replace command/args Docker format with container key in renderMCPFetchServerConfig for both JSON (Gemini, Claude, Codex) and TOML (Codex) output formats. This fixes schema validation failures: - missing properties: 'container' - additionalProperties 'command', 'args' not allowed Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-02-23T03:35:34Z

@copilot add add web-fetch to smoke-plod and smoke-codex. And to smoke copilot.

…smoke-copilot - smoke-codex.md: add web-fetch tool + test step 4 (Web Fetch Testing) - smoke-gemini.md: add web-fetch tool + test step 2 (Web Fetch Testing) - smoke-copilot.md: add web-fetch test step 5 (already had web-fetch tool) - Recompile lock files with correct container format for web-fetch MCP server Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-02-23T03:44:01Z

@copilot add add web-fetch to smoke-plod and smoke-codex. And to smoke copilot.

Done in d9b5066:

smoke-codex: added web-fetch: to tools + "Web Fetch Testing" step (step 4)
smoke-gemini (smoke-plod): added web-fetch: to tools + "Web Fetch Testing" step (step 2)
smoke-copilot: already had web-fetch: in tools — added "Web Fetch Testing" step (step 5)

All three lock files now contain "container": "mcp/fetch" (the correct MCP Gateway format fixed in this PR).

github-actions · 2026-02-23T03:48:15Z

✨ The prophecy is fulfilled... Smoke Codex has completed its mystical journey. The stars align. 🌟

github-actions · 2026-02-23T03:48:17Z

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

github-actions · 2026-02-23T03:48:17Z

🎬 THE END — Smoke Claude MISSION: ACCOMPLISHED! The hero saves the day! ✨

github-actions · 2026-02-23T03:53:20Z

🤖 Smoke test 22292196548 results for PR #17822:

Test	Status
GitHub MCP	✅
Safe Inputs GH CLI	✅
Serena MCP	❌
Playwright	❌
Web Fetch	✅
File Writing	✅
Bash Tool	✅
Discussion Interaction	✅
Build gh-aw	✅
Discussion Creation	✅
Workflow Dispatch	✅
PR Review	✅

Overall: ⚠️ PARTIAL PASS (Serena/Playwright not available in Copilot context)

PR author: @app/copilot-swe-agent | Run: §22292196548

📰 BREAKING: Report filed by Smoke Copilot

github-actions

This PR adds web-fetch MCP server support to the smoke-codex workflow, enabling the web_fetch tool test. Changes look correct — the container image is properly registered in both the download list and MCP server config. Minor suggestion: consider pinning the mcp/fetch image to a specific version for reproducibility.

📰 BREAKING: Report filed by Smoke Copilot

.github/workflows/smoke-codex.md

github-actions · 2026-02-23T03:53:22Z

.github/workflows/smoke-codex.lock.yml

            "${GITHUB_WORKSPACE}"
          ]
          mounts = ["${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE}:rw"]
+


The mcp/fetch container image is included in the download list and wired up correctly in the MCP server config. One minor note: the image mcp/fetch doesn't specify a version tag — consider pinning to a specific version (e.g., mcp/fetch:latest or a digest) for reproducibility.

github-actions · 2026-02-23T03:53:31Z

Smoke test results:
PRs: #17824 [jsweep] Clean close_discussion.cjs; #17819 Fix smoke-copilot golden file to include --browser-arg --no-sandbox in Playwright entrypointArgs
GitHub MCP (2 merged PRs): ✅
Serena MCP (activate+find_symbol>=3): ✅
Playwright MCP (page title): ❌ (tool unavailable)
Web fetch https://github.com contains GitHub: ✅
File write+cat: ✅ | Build make build: ✅ | Overall: FAIL

🔮 The oracle has spoken through Smoke Codex

github-actions · 2026-02-23T03:53:35Z

📰 VERDICT: Smoke Copilot has concluded. All systems operational. This is a developing story. 🎤

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

github-actions · 2026-02-23T03:57:26Z

✅ Commit pushed: 32f1740

github-actions · 2026-02-23T03:57:30Z

Smoke Test Results - Run §22292196576

Test	Status
1. GitHub MCP	✅
2. Safe Inputs GH CLI	✅
3. Serena MCP	✅
4. Make Build	✅
5. Playwright	⚠️ (fallback)
6. Tavily Search	✅
7. File Writing	✅
8. Bash Tool	✅
9. Discussion Comment	✅
10. Agentic Workflows MCP	✅
11. Update PR	✅
12. Review Comments	✅
13. Submit Review	✅
14. Resolve Thread	✅
15. Add Reviewer	✅
16. Push to Branch	✅
17. Close PR	⚠️ (skipped)

Overall: PARTIAL (2 skipped/fallback)

💥 [THE END] — Illustrated by Smoke Claude

github-actions

💥 Automated smoke test review - all systems nominal!

💥 [THE END] — Illustrated by Smoke Claude

Copilot

Pull request overview

Fixes invalid MCP Gateway configuration generation for tools: web-fetch by emitting a gateway-schema-compliant container server shape (instead of command/args), and updates tests and smoke workflows/locks accordingly.

Changes:

Update renderMCPFetchServerConfig to render "container": "mcp/fetch" for JSON and container = "mcp/fetch" for TOML.
Adjust unit/integration tests to assert the new container shape.
Extend Gemini/Codex/Copilot smoke workflows and regenerated lock files to exercise web-fetch and include the mcp/fetch image/config.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pkg/workflow/fetch.go	Emit gateway-compliant `container` config for the web-fetch MCP server.
pkg/workflow/fetch_test.go	Update assertions for the new JSON/TOML rendering shape.
pkg/workflow/fetch_integration_test.go	Update integration assertions to check `container = "mcp/fetch"` / `"container": "mcp/fetch"`.
.github/workflows/smoke-gemini.md	Add `web-fetch` tool + a dedicated smoke step to validate it.
.github/workflows/smoke-gemini.lock.yml	Regenerate lock to include `mcp/fetch` image download and `web-fetch` MCP server config.
.github/workflows/smoke-codex.md	Add `web-fetch` tool + a dedicated smoke step to validate it.
.github/workflows/smoke-codex.lock.yml	Regenerate lock to include `mcp/fetch` image download and `web-fetch` MCP server config (TOML + JSON).
.github/workflows/smoke-copilot.md	Add a dedicated `web-fetch` smoke step (tool already present).
smoke-test-claude-22292196576.md	Add smoke-test run marker file.

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Copilot · 2026-02-23T05:33:58Z

pkg/workflow/fetch.go

 	// Add the web-fetch server configuration
 	// Note: The "container" key marks this as an MCP server with stdio transport.
 	// The actual rendering is done by renderMCPFetchServerConfig() which uses
 	// the standardized Docker command format for all engines.
 	webFetchConfig := map[string]any{


The comment above webFetchConfig says renderMCPFetchServerConfig() uses a “standardized Docker command format”, but the renderer now emits a gateway-schema container key (no docker command/args). Please update the comment to reflect the container-based MCP Gateway shape to avoid misleading future changes.

See below for a potential fix:

// The actual rendering is done by renderMCPFetchServerConfig(), which emits // the MCP Gateway container-based schema (using the \"container\" field) for all engines.

Initial plan

f72356c

Copilot AI assigned Copilot and pelikhan Feb 23, 2026

Copilot started work on behalf of pelikhan February 23, 2026 03:13 View session

Copilot AI changed the title ~~[WIP] Fix web-fetch compilation to valid MCP Gateway config~~ fix: web-fetch MCP server generates container format instead of command/args Feb 23, 2026

Copilot finished work on behalf of pelikhan February 23, 2026 03:27

Copilot started work on behalf of pelikhan February 23, 2026 03:35 View session

Copilot finished work on behalf of pelikhan February 23, 2026 03:44

pelikhan added the smoke label Feb 23, 2026

github-actions bot mentioned this pull request Feb 23, 2026

Smoke Test: Copilot - 22292196548 #17826

Closed

github-actions bot added smoke-copilot and removed smoke labels Feb 23, 2026

github-actions bot reviewed Feb 23, 2026

View reviewed changes

test: Add smoke test file for run 22292196576

32f1740

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

github-actions bot mentioned this pull request Feb 23, 2026

Smoke Test: Claude - 22292196576 #17827

Closed

github-actions bot added the smoke-claude label Feb 23, 2026

github-actions bot reviewed Feb 23, 2026

View reviewed changes

pelikhan marked this pull request as ready for review February 23, 2026 05:28

Copilot AI review requested due to automatic review settings February 23, 2026 05:28

pelikhan merged commit 0d5e2e0 into main Feb 23, 2026

pelikhan deleted the copilot/fix-web-fetch-config branch February 23, 2026 05:28

Copilot started reviewing on behalf of pelikhan February 23, 2026 05:29 View session

Copilot AI reviewed Feb 23, 2026

View reviewed changes

github-actions bot mentioned this pull request Feb 23, 2026

[Daily Report] Daily Status Report — 2026-02-23 #17866

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Actual generated lock output

Expected

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