> 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-platform/use-harness-ai/connect-with-ai/index/tools-reference.md).

# Tools reference

The 11 MCP tools exposed by the Harness MCP Server, with request examples, the pipeline run workflow, and MCP resource URIs.

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

{% @harness-feedback/feedback module="harness-ai" pagePath="harness-ai/use-harness-ai/connect-with-ai/index/tools-reference" %}