Add `stdio` transport support to client integration test runner by Copilot · Pull Request #77 · advanced-security/codeql-development-mcp-server

Copilot · 2026-02-23T16:07:18Z

Integration Testing Improvement PR: MCP Server Primitives

Related Issue: #76

⚠ Scope Guard: This PR extends beyond client/integration-tests/** by necessity — the integration test runner infrastructure, CI workflow, and documentation all required updates to support dual-transport testing. No server code changes.

Summary

Client integration tests only exercised the HTTP transport, but stdio is the default (and most common) mode for end users. This PR adds StdioClientTransport support to the MCP client so integration tests can run against either transport, defaults everything to stdio, and updates CI to matrix-test both modes. The MCP_MODE env var is normalized to lowercase and only an explicit value of "http" triggers HTTP transport — all other values (including typos or case variations) default to stdio, consistent across both the JS client and the bash runner.

Primitive Metadata

Primitive name(s): All MCP tools (transport-layer change, not tool-specific)
Type(s): Combination
Related resources or prompts (if any): N/A

Test Additions / Modifications

No new test cases — the existing integration tests now run over both transports.

client/src/ql-mcp-client.js: connect() branches on MCP_MODE env var (normalized to lowercase, stdio default). Only MCP_MODE=http triggers HTTP transport; all other values use StdioClientTransport. Server path configurable via MCP_SERVER_PATH.
client/scripts/run-integration-tests.sh: Skips manual server start/stop/wait in stdio mode (client manages lifecycle). MCP_MODE defaults to stdio. Uses shift 2 in run_tests_in_mode() so internal positional args (mode_name, enable_monitoring) are not forwarded to the node CLI.
client/package.json: Added test:integration:http and test:integration:stdio scripts.
client/src/lib/cli-parser.js: Documented new env vars (MCP_MODE, MCP_SERVER_PATH, MCP_SERVER_URL, ENABLE_MONITORING_TOOLS) in help text.
.github/workflows/client-integration-tests.yml: Added mcp-mode: [http, stdio] matrix dimension. Server cleanup conditional on HTTP mode.
docs/testing.md: Documents stdio as default transport for Layer 2a.
docs/getting-started.md, docs/public.md: Recommend VSIX installation as primary method.

Before vs After File States

N/A — no fixture file changes. The transport layer is transparent to test assertions.

Assertions Added

Tool result validation (success, error handling)
Other: Existing test assertions now validated over both stdio and HTTP transports via CI matrix

Edge & Negative Cases

stdio mode: StdioClientTransport spawns server as child process — if server crashes, transport surfaces the error naturally via MCP SDK
HTTP cleanup step in CI gated on matrix.mcp-mode == 'http' to avoid no-op failures in stdio runs
MCP_MODE is case-insensitive: STDIO, Stdio, stdio all resolve to stdio transport; only http (any case) triggers HTTP — consistent between the JS client and bash runner

Non-Goals / Deferred Follow-ups

No changes to individual test fixtures or assertions
Monitoring-mode tests (session_* tools) unchanged — they work identically over both transports

Local Verification

# Full lint + format + server unit tests
npm run tidy:check && npm run test:server  # ✅

# CodeQL security scan
# 0 alerts

CI will validate actual integration test execution over both transports via the updated matrix.

Checklist

Screenshots / Logs (Optional)

N/A — transport-layer change; no visible output differences.

Additional Notes

The scope guard is intentionally exceeded: this is a test infrastructure change (runner + CI + docs), not a test case change. The StdioClientTransport import comes from the existing @modelcontextprotocol/sdk dependency — no new packages added.

Maintainers: Reject or request split if scope exceeds integration test boundaries.

Original prompt

This section details on the original issue you should resolve

<issue_title>Update client integration test runner to validate MCP server functionality in stdio mode</issue_title>
<issue_description>## Problem to Resolve

Client integration tests currently only test the HTTP run mode of the codeql-development-mcp-server, even though it supports both http and stdio MCP server run modes.

Expected Outcomes

Client integration tests need to be able to test either mode of the MCP server, especially since the stdio run mode is the default mod that most users will use for the MCP server.

Actions workflows for client integration tests must test both server run modes.

The default "npm run build-and-test" must test against just stdio mode by default.

The client integration test runner must be updated as needed to support these requirements.

The docs/testing.md documentation must accurately reflect the requirements for testing the stdio mode as the primary/default run mode for codeql-development-mcp-server.

The docs/public.md and docs/getting-started.md documentation files must recommend / prefer the vscode-codeql-development-mcp-server installation method (from release VSIX archive bundle).</issue_description>

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

Custom agent used: ql-mcp-tool-tester
An agent for testing and validating tools for the latest QL Development MCP Server.

Fixes Update client integration test runner to validate MCP server functionality in stdio mode #76

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

- Update client to support both stdio and http transport modes (MCP_MODE env var, default: stdio) - In stdio mode, client spawns server via StdioClientTransport from MCP SDK - Update run-integration-tests.sh to skip manual server start/stop in stdio mode - Add test:integration:http and test:integration:stdio scripts to client/package.json - Update CI workflow to test both transport modes via matrix strategy - Update docs/testing.md to document stdio as default transport - Update docs/getting-started.md and docs/public.md to recommend VSIX installation Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>

Add MCP_SERVER_PATH env var support for configuring the server binary path in stdio mode. Update CLI help text to document new environment variables. Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>

github-actions · 2026-02-23T17:30:28Z

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

Bug 1 — CWD mismatch in stdio mode (both platforms): StdioClientTransport inherited the client/ working directory, so relative paths passed to CodeQL CLI (e.g. server/ql/javascript/...) resolved to client/server/ql/... which does not exist. Add cwd: repoRoot to the transport options to match the HTTP-mode behavior where start-server.sh explicitly cd's to the repo root. Bug 2 — False success on Windows in stdio mode: StdioClientTransport.close() could cause an abrupt process exit on Windows before printTestSummary() and process.exit(exitCode) were reached, so the shell script saw exit code 0 and reported success despite test failures. Move summary printing and process.exitCode assignment above the disconnect() call in all four run methods so results are always reported even if disconnect triggers an early exit.

Copilot

Pull request overview

Adds dual-transport support to the client-side integration test infrastructure so the existing MCP tool integration tests can run against the server over either stdio (default) or HTTP, and updates CI/docs accordingly (no server tool changes).

Changes:

Update client/src/ql-mcp-client.js to select StdioClientTransport vs StreamableHTTPClientTransport based on MCP_MODE (defaulting to stdio) and support MCP_SERVER_PATH for stdio runs.
Update the integration test runner script + client package scripts to support explicit stdio/http modes, with lifecycle management differences between transports.
Update GitHub Actions workflow and documentation to reflect stdio as the primary/default transport and recommend VSIX installation.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
`client/src/ql-mcp-client.js`	Adds stdio transport support and mode-aware logging/exit flow for integration runs.
`client/scripts/run-integration-tests.sh`	Adds `MCP_MODE` defaulting to stdio and avoids HTTP server lifecycle steps when running stdio.
`client/package.json`	Adds explicit `test:integration:http` / `test:integration:stdio` scripts and aligns monitoring script flags.
`client/src/lib/cli-parser.js`	Documents new env vars (`MCP_MODE`, `MCP_SERVER_PATH`, etc.) in CLI help output.
`.github/workflows/client-integration-tests.yml`	Adds a `mcp-mode: [http, stdio]` matrix and gates HTTP cleanup steps.
`docs/testing.md`	Documents dual transport modes and notes stdio as the default transport for integration tests.
`docs/public.md`	Recommends VSIX/extension installation as the primary path; keeps npm as an alternative.
`docs/getting-started.md`	Clarifies VSIX install steps and reinforces extension-first onboarding.
`.gitignore`	Ignores additional client query output artifacts to prevent accidental commits.

client/scripts/run-integration-tests.sh

client/src/ql-mcp-client.js

data-douser · 2026-02-23T19:40:47Z

@copilot apply changes based on the comments in this thread

…warding - Normalize MCP_MODE to lowercase in client constructor so that MCP_MODE=STDIO works the same as MCP_MODE=stdio - Select stdio transport by default; only use HTTP when MCP_MODE === "http" (previously any non-"stdio" value fell through to HTTP) - Add shift 2 in run_tests_in_mode() so mode_name and enable_monitoring positional args are not forwarded to node as extra CLI arguments Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>

Copilot · 2026-02-23T19:47:19Z

@copilot apply changes based on the comments in this thread

Both review comments addressed in 04661fb:

run_tests_in_mode() now uses shift 2 so internal args aren't forwarded to node
MCP_MODE normalized to lowercase; stdio is the default transport (only "http" triggers HTTP)

Initial plan

ccc9c77

Copilot AI assigned Copilot and data-douser Feb 23, 2026

Copilot started work on behalf of data-douser February 23, 2026 16:07 View session

Copilot AI and others added 2 commits February 23, 2026 16:20

Copilot AI changed the title ~~[WIP] Update client integration test runner for MCP server functionality~~ Add stdio transport support to client integration test runner Feb 23, 2026

Copilot finished work on behalf of data-douser February 23, 2026 16:29

Fixes for stdio-based client integration tests

87e5248

data-douser added the enhancement New feature or request label Feb 23, 2026

data-douser changed the title ~~Add stdio transport support to client integration test runner~~ Add stdio transport support to client integration test runner Feb 23, 2026

data-douser marked this pull request as ready for review February 23, 2026 19:12

data-douser requested review from a team, data-douser and enyil as code owners February 23, 2026 19:12

Copilot AI review requested due to automatic review settings February 23, 2026 19:12

Copilot started reviewing on behalf of data-douser February 23, 2026 19:13 View session

data-douser approved these changes Feb 23, 2026

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Copilot AI reviewed Feb 23, 2026

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Copilot started work on behalf of data-douser February 23, 2026 19:40 View session

Copilot finished work on behalf of data-douser February 23, 2026 19:48

data-douser enabled auto-merge (squash) February 23, 2026 20:59

data-douser approved these changes Feb 23, 2026

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data-douser disabled auto-merge February 23, 2026 23:28

data-douser merged commit 4baf6af into main Feb 23, 2026
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data-douser deleted the copilot/update-client-integration-test-runner branch February 23, 2026 23:28

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Add `stdio` transport support to client integration test runner#77

Add `stdio` transport support to client integration test runner#77
data-douser merged 6 commits intomainfrom
copilot/update-client-integration-test-runner

Copilot AI commented Feb 23, 2026 •

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Integration Testing Improvement PR: MCP Server Primitives

Summary

Primitive Metadata

Test Additions / Modifications

Before vs After File States

Assertions Added

Edge & Negative Cases

Non-Goals / Deferred Follow-ups

Local Verification

Checklist

Screenshots / Logs (Optional)

Additional Notes

Expected Outcomes

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

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Copilot AI commented Feb 23, 2026 •

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