Gatling MCP

Gatling MCP

The tool schemas define valid request shapes. Check each tool's own description directly rather than assuming from a sibling (e.g. read vs. write variants of the same resource aren't guaranteed to share a role floor, and a location's listing doesn't expose all of its capabilities).

Never call the Gatling Enterprise API directly (v1 or v2, via curl, a raw HTTP request, or any tool other than these MCP tools), even as a fallback when an MCP tool call fails. Always go through these MCP tools, and report failures to the user instead of working around them.

Tools

There is no packages.create_one / packages.delete_one: packages can only be produced by actually building and uploading an artifact, never through this MCP. If a build-tool skill/integration for packaging (e.g. one that drives the Enterprise Maven/Gradle/sbt/npm plugin's package goal) is available in the environment, prefer it over telling the user to do this by hand. This holds even if a hypothetical packages.create_one existed, since packaging is fundamentally a build step an API call can't substitute for.

Terminology

• Test: a saved, runnable definition of what to run (source), where (distribution.loadGenerators), and under what conditions to stop (execution.stopCriteria). Running it produces a run.
• Source, on a test, is one of:
  • build_from_sources: sourceRepositoryId + buildTool (maven, maven-wrapper, gradle, gradle-wrapper, sbt, npm, or custom with an explicit command/packageFormat) + simulation (fully-qualified class/id), optional branch/workingDirectory. Built fresh from git on every run. Prefer one of the named build tools over custom whenever the project actually uses one of them. custom means hand-specifying the build command and output format, which is more error-prone and should be a fallback, not a default.
  • packaged: packageId + simulation. Runs a pre-built artifact as-is.
• Source repository: a registered git remote (remote.url) a test can build from. Metadata only (name/URL): auth (deploy key, PAT) isn't settable via create_one's schema, so private repos likely still need credentials configured through Control Plane Builders.
• Package: a pre-built artifact (_format: jvm or js) uploaded outside the MCP.
• Location, in distribution.loadGenerators[].locationId: either a plain managed location name (a Gatling-hosted public region, e.g. "Europe - Paris") or a private location id (starts with prl_). Same field, two different ID spaces. A private location's artifactFormats must include the format of what you're running (a jvm-only location can't run a js package/build).
• Team: the ownership/permission boundary. Every package, source repository, and test belongs to a team; roles are granted per team.
• Roles: granted per team, not globally. Having Configure on one team says nothing about another. At least Read, Configure, and Start appear across these tools as distinct levels; don't assume one implies another.
• Credits: consumed by tests.start_one (an actual run), not by any create/patch/delete/read call. Those only touch definitions or return data.

Recommended workflows

Create a test for a project that already has a source repository or package registered:

1. teams.read_all, source_repositories.read_all and/or packages.read_all to find the real teamId/sourceRepositoryId/packageId. These are opaque IDs, never invent or reuse one from memory without reconfirming it still exists.
2. locations.read_all to pick a locationId, checking artifactFormats against the package/build format if using a private location, and, for build_from_sources on a private location, confirming separately that it's a Control Plane Builder (see Caveats).
3. tests.create_one with a source matching the actual project's language/build tool (see Caveats).
4. Confirm the resulting test looks right (tests.read_one) before calling tests.start_one, since starting spends credits and produces a visible run.

Onboard a project that isn't registered anywhere yet:

1. Check source_repositories.read_all / packages.read_all first. It may already be there under a name you don't expect.
2. If it's a git-buildable project, source_repositories.create_one (name, teamId, remote.url) registers it directly, no need to tell the user to do this by hand. For a private repo, flag that credentials may still need to be set up in the Control Plane Builder if the run later fails to clone.
3. If it's meant to run from a pre-built artifact instead, there's no equivalent create call. Use a build-tool skill/integration if one is available to build and upload it, otherwise that step has to happen outside the MCP (build plugin or UI); packages.read_all will pick it up once it exists.

Investigate a run: runs.read_run_logs for what happened during execution (build/injection/crash errors); runs.read_report_requests for the performance numbers, narrowed with from/to if only part of the run matters.

Caveats

• Build tool / format must match the actual project. A Java/Maven project needs buildTool.type: "maven" (or maven-wrapper) against a repo that's actually that Maven project, or a packaged source whose _format is jvm. If the only registered source/package doesn't match the project you're actually being asked about, don't substitute it silently. A mismatch fails the build/run, it doesn't degrade gracefully. Say there's no matching source and ask how to proceed (register the real one via source_repositories.create_one, or confirm the mismatch is intentional).
• tests.create_one's execution object is fully required, even fields that are logically optional in spirit. systemProperties, environmentVariables, stopCriteria must be present (empty object/array is fine), unlike tests.patch_one where the same fields are optional.
• locationId is overloaded: a managed location is matched by name string, a private location by its prl_...-style id. Don't assume one format for both.
• A build_from_sources test needs a Control Plane Builder if it runs on a private location. Only a private location whose Control Plane is deployed in Builder mode can build from git. A plain (load-generator-only) Control Plane can only run pre-packaged artifacts. locations.read_all doesn't expose this: a private location's entry is just {id, artifactFormats, description}, with nothing indicating whether it can build. Don't assume a private location supports build_from_sources just because its artifactFormats matches. Confirm with the user or point them at Build from Git on private locations before wiring one up. Managed (public) locations aren't affected as packages are already built.

Troubleshooting

MCP tool call fails

If any MCP tool call fails, check authentication first:

1. Verify GATLING_ENTERPRISE_API_TOKEN is set in the environment.
2. If missing, warn the user, suggest using direnv, and offer to create a .envrc file.
3. Never print the actual token value in the terminal or logs.
4. The token needs at least the Configure role on Gatling Enterprise.