Harness DSL — one source of truth per plugin

Every OMA plugin describes its runtime surface in a single YAML file:

plugins/<name>/<name>.oma.yaml

python -m tools.oma_compile translates that file into the native files Claude Code and Kiro already understand:

<plugin>.oma.yaml  ──(oma-compile)──▶  .mcp.json
                                   ▶  kiro-agents/<agent>.agent.json
                                   ▶  .omao/triggers.json   (merged across plugins)
                                   ▶  hooks/hooks.json       (PreToolUse enforcement)
                                   ▶  hooks/harness-rules.json + hooks/enforce.py

Plugins keep shipping the compiled output, so /plugin install from the marketplace works even on machines that have never seen the compiler.

Example

# plugins/ai-infra/ai-infra.oma.yaml
version: 1
plugin: ai-infra

agents:
  - id: autopilot-deploy
    runtime: claude-code
    mcp: [eks, cloudwatch, prometheus]
    tier: 0
    ontology:
      produces: [Deployment]
      consumes: [Spec, ADR]

mcp:
  eks:
    command: uvx
    args: ["awslabs.eks-mcp-server==0.1.28"]
    env: { FASTMCP_LOG_LEVEL: ERROR }
  cloudwatch:
    command: uvx
    args: ["awslabs.cloudwatch-mcp-server==0.0.25"]

hooks:
  session-start:
    runs: hooks/session-start.sh

triggers:
  - keyword: platform-bootstrap
    route: /oma:platform-bootstrap

Guarantees enforced at compile time

Pinned MCP versions. args must contain ==X.Y.Z. Floating versions (@latest, unpinned, caret ranges) are rejected so a compromised upstream release cannot silently land alongside AWS credentials.
Declared MCP references. agents[*].mcp can only name ids that exist in the top-level mcp: map. Unknown references fail the build.
Real hook scripts. hooks.<event>.runs must point at an existing file under the plugin. No phantom hook declarations.
Valid enforcement rules. Every policies[].enforce.deny_if regex must compile, or the build fails — a broken rule can never ship and silently stop enforcing (fail-closed at build time).
Stable output. Emitted JSON is sorted deterministically; CI fails the build if committed .mcp.json or .agent.json drift from the DSL source (oma-compile --check).

Runtime enforcement (`policies`)

A policies entry turns a declarative rule into real enforcement — pure Claude Code, no external policy engine and no opa binary. The compiler emits hooks/harness-rules.json plus a PreToolUse entry in hooks/hooks.json that runs the bundled hooks/enforce.py. Because the hook fires at the harness layer before a tool executes, a denied call never reaches the model — this is enforcement, not prompt-level guidance.

policies:
  - id: deny-eks-mutating-kubectl
    severity: blocking
    phase: [construction, operations]
    description: Block mutating kubectl; EKS writes need an approved Deployment.
    enforce:
      tool: Bash                       # omit to match every tool
      deny_if:
        command_matches: "kubectl\\s+(apply|create|delete|patch|exec|rollout)"
      decision: deny                   # deny | ask
      reason: "Harness: mutating kubectl is blocked. Use platform-bootstrap."

deny_if supports command_matches, command_matches_any (list), file_path_matches (Write/Edit), and input_field ({path, matches}). A rule fires when the tool matches and every declared condition matches; the first firing rule wins. At runtime the enforcer fails open only when no ruleset is present, and fails closed when a shipped ruleset is unreadable. See the Harness DSL v2 page for the full enforcement model and a before/after (OPA → pure-CC) migration example.

Commands

# Compile one plugin
python -m tools.oma_compile plugins/ai-infra/ai-infra.oma.yaml

# Compile every plugin that has a *.oma.yaml
python -m tools.oma_compile --all

# Fail if committed native files drift from DSL
python -m tools.oma_compile --check

Where the ontology plugs in

agents[*].ontology.produces and consumes use the entity enum from schemas/ontology/agent.schema.json. The compiler doesn't invent new vocabulary — the Ontology page (Ontology) is the source of truth.

Schema reference

Full JSON Schema: schemas/harness/dsl.schema.json.

Example​

Guarantees enforced at compile time​

Runtime enforcement (policies)​

Commands​

Where the ontology plugs in​

Schema reference​