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.

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Available tools

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 to review the 139 supported resource types and the operations each one accepts.

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Tool examples

Discover available resources:

{ "resource_type": "pipeline" }

List pipelines in a project:

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

Get a specific service:

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

Run a pipeline:

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

Toggle a feature flag:

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

Search across all resource types:

{ "query": "payment-service" }

Diagnose a failed execution:

{ "execution_id": "abc123XYZ" }

Diagnose from a Harness URL:

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

Get project health status:

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

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Pipeline run workflow

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.

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Pipeline storage modes

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.

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MCP resources

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 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

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Next steps

• Resource types: Review every resource type and its supported operations.

• Prompt templates: Start from a pre-built workflow instead of raw tool calls.

• Approvals and safety: Understand how write tools request confirmation.