Harness MCP Server

harness_schema

Read-only

Get the JSON Schema for a Harness resource type (pipeline, template, or trigger) to understand the required body structure for create or update operations. Optionally drill into specific sections with a dot-separated path.

Instructions

Fetch Harness YAML schema for a resource type. Returns the JSON Schema definition so you know the exact body structure for harness_create/harness_update. Use without path for a summary of fields and available sections. Use with path to drill into a specific section (e.g. path='scheduled_trigger' for cron trigger spec). Available schemas: pipeline, template, trigger.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "resource_type": "<resource_type>"
    },
    "name": "harness_schema"
  }
}

Input Schema

Name	Required	Description	Default
`resource_type`	Yes	Schema to fetch: pipeline, template, or trigger
`path`	No	Dot-separated path to drill into a specific definition section. E.g. 'trigger_source' for source types, 'scheduled_trigger' for cron spec, 'webhook_trigger' for webhook spec. Omit for a top-level summary.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.8.3Jun 22, 2026

TDQS

A4.4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Describes return type (JSON Schema definition) and path parameter behavior, adding value beyond annotations that already indicate read-only and open world. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two focused sentences plus a list of schemas; no wasted words. Front-loaded with main purpose, then specifics.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given annotations cover safety and open world, and schema covers parameters, description provides adequate context on path behavior and available schemas. No output schema but mentions return type.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema coverage, description enhances understanding by explaining path usage with examples and reiterating enum values for resource_type, going beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Fetch Harness YAML schema for a resource type' with specific verb and resource, and explains its purpose for knowing body structure for harness_create/harness_update, distinguishing it from siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides clear guidance on using without path for summary and with path to drill into sections, along with available schemas. Lacks explicit 'when not to use', but context is sufficient.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server