> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/harness-ai/untitled-1/use-harness-ai/ide-and-integrations/mcp-server/tools-reference.md).

# Tools reference

The server exposes 11 MCP tools. Most accept `org_id` and `project_id` as optional overrides. If omitted, they fall back to `HARNESS_ORG` and `HARNESS_PROJECT` (or the deprecated `HARNESS_DEFAULT_ORG_ID` and `HARNESS_DEFAULT_PROJECT_ID`). Most tools also accept a `url` parameter, so you can paste a Harness UI URL and the server auto-extracts identifiers.

***

### Available tools <a href="#available-tools" id="available-tools"></a>

| Tool               | Description                                                                                                                          |
| ------------------ | ------------------------------------------------------------------------------------------------------------------------------------ |
| `harness_describe` | Discover available resource types, operations, and fields. No API call, because it returns local registry metadata.                  |
| `harness_schema`   | Fetch JSON Schema definitions for creating and updating resources. Supports deep drilling via the `path` parameter                   |
| `harness_list`     | List resources of a given type with filtering, search, and pagination                                                                |
| `harness_get`      | Get a single resource by its identifier                                                                                              |
| `harness_create`   | Create a new resource. Prompts for user confirmation via elicitation                                                                 |
| `harness_update`   | Update an existing resource. Prompts for user confirmation via elicitation                                                           |
| `harness_delete`   | Delete a resource. Prompts for user confirmation via elicitation                                                                     |
| `harness_execute`  | Execute an action on a resource (run or retry a pipeline, toggle a flag, sync an app). Prompts for user confirmation via elicitation |
| `harness_search`   | Search across multiple resource types in parallel with a single query                                                                |
| `harness_diagnose` | Diagnose pipeline, connector, delegate, and GitOps application resources with structured failure analysis                            |
| `harness_status`   | Get a real-time project health dashboard with recent executions, failure rates, and deep links                                       |

Each tool routes to a `resource_type`. Go to [Resource types](/harness-ai/use-harness-ai/harness-ai/connect-with-ai/harness-mcp-server/resource-types.md) to review the 139 supported resource types and the operations each one accepts.

***

### Tool examples <a href="#tool-examples" id="tool-examples"></a>

**Discover available resources**:

```json
{ "resource_type": "pipeline" }
```

**List pipelines in a project**:

```json
{ "resource_type": "pipeline", "search_term": "deploy", "size": 10 }
```

**Get a specific service**:

```json
{ "resource_type": "service", "resource_id": "my-service-id" }
```

**Run a pipeline**:

```json
{
  "resource_type": "pipeline",
  "action": "run",
  "resource_id": "my-pipeline",
  "inputs": { "tag": "v1.2.3" }
}
```

**Toggle a feature flag**:

```json
{
  "resource_type": "feature_flag",
  "action": "toggle",
  "resource_id": "new_checkout_flow",
  "enable": true,
  "environment": "production"
}
```

**Search across all resource types**:

```json
{ "query": "payment-service" }
```

**Diagnose a failed execution**:

```json
{ "execution_id": "abc123XYZ" }
```

**Diagnose from a Harness URL**:

```json
{ "url": "https://app.harness.io/ng/account/.../pipelines/myPipeline/executions/abc123XYZ/pipeline" }
```

**Get project health status**:

```json
{ "org_id": "default", "project_id": "my-project", "limit": 5 }
```

***

### Pipeline run workflow <a href="#pipeline-run-workflow" id="pipeline-run-workflow"></a>

You can reduce execution-time input errors with the following:

1. **Discover required runtime inputs**:\
   `harness_get(resource_type="runtime_input_template", resource_id="<pipeline_id>")`\
   The returned template shows `<+input>` placeholders that need values.
2. **Choose input strategy**:
   * **Simple variables**: Pass flat key-value `inputs` (for example, `{"branch":"main","env":"prod"}`).
   * **Complex inputs**: Use `input_set_ids` for CI codebase or build blocks and nested template inputs.
   * **CI codebase shorthand keys**:

     | Shorthand key | Expanded structure                                     |
     | ------------- | ------------------------------------------------------ |
     | `branch`      | `build.type=branch`, `build.spec.branch=<value>`       |
     | `tag`         | `build.type=tag`, `build.spec.tag=<value>`             |
     | `pr_number`   | `build.type=PR`, `build.spec.number=<value>`           |
     | `commit_sha`  | `build.type=commitSha`, `build.spec.commitSha=<value>` |
3. **Execute the run**:\
   `harness_execute(resource_type="pipeline", action="run", resource_id="<pipeline_id>", ...)`

If required fields are unresolved, the tool returns a pre-flight error with expected keys and suggested input sets.

***

### Pipeline storage modes <a href="#pipeline-storage-modes" id="pipeline-storage-modes"></a>

Harness MCP Server supports three storage modes that determine where a pipeline's YAML lives.

| Mode                      | Description                                            | When to use                                                       |
| ------------------------- | ------------------------------------------------------ | ----------------------------------------------------------------- |
| **Inline**                | Pipeline YAML stored in Harness                        | Default. Simplest setup, no Git required                          |
| **Remote (External Git)** | Pipeline YAML in GitHub, GitLab, Bitbucket, or similar | Teams using Git-backed pipeline-as-code with an external provider |
| **Remote (Harness Code)** | Pipeline YAML in a Harness Code repository             | Teams using the built-in Harness Git hosting                      |

For remote pipelines, pass `store_type`, `connector_ref` (or `is_harness_code_repo`), `repo_name`, `branch`, `file_path`, and `commit_msg` in the `params` object when you call `harness_create` or `harness_update`.

***

### MCP resources <a href="#mcp-resources" id="mcp-resources"></a>

In addition to tools, the server exposes MCP **resources**, which are read-only documents addressable by URI. These are a protocol primitive and are distinct from the Harness [resource types](/harness-ai/use-harness-ai/harness-ai/connect-with-ai/harness-mcp-server/resource-types.md) that tools operate on.

| Resource URI                                   | Description                          | MIME Type                 |
| ---------------------------------------------- | ------------------------------------ | ------------------------- |
| `pipeline:///{pipelineId}`                     | Pipeline YAML definition             | `application/x-yaml`      |
| `pipeline:///{orgId}/{projectId}/{pipelineId}` | Pipeline YAML (with explicit scope)  | `application/x-yaml`      |
| `executions:///recent`                         | Last 10 pipeline execution summaries | `application/json`        |
| `schema:///pipeline`                           | Harness pipeline JSON Schema         | `application/schema+json` |
| `schema:///template`                           | Harness template JSON Schema         | `application/schema+json` |
| `schema:///trigger`                            | Harness trigger JSON Schema          | `application/schema+json` |

***

### Next steps <a href="#next-steps" id="next-steps"></a>

* [Resource types](/harness-ai/use-harness-ai/harness-ai/connect-with-ai/harness-mcp-server/resource-types.md): Review every resource type and its supported operations.
* [Prompt templates](/harness-ai/use-harness-ai/harness-ai/connect-with-ai/harness-mcp-server/prompt-templates.md): Start from a pre-built workflow instead of raw tool calls.
* [Approvals and safety](/harness-ai/use-harness-ai/harness-ai/connect-with-ai/harness-mcp-server/approvals-and-safety.md): Understand how write tools request confirmation.