> ## Documentation Index
> Fetch the complete documentation index at: https://docs.deeda.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Harness Overview

> One control plane, any model, any provider, full capability.

The deeda agent harness drives any foundational model — Anthropic, OpenAI,
Gemini, or local — across every surface (API, SDK, MCP, CLI) from a single
workflow-markdown control plane.

## The pieces

**Workflow markdown is where you define a run.** A `workflow.md` file declares
the runtime, budget, tools, sandbox, retries, review rules, state machine, and
selection policy. You write *what* should happen, never imperative provider code.

**Cadence owns the run.** Cadence is a local Elixir/OTP sidecar that validates
workflow frontmatter, reduces it to a run payload, owns ticket lifecycle and
budgets, performs provider selection, and advances workflows from typed
harness events on a `:harness` event bus. Dispatchers are pure executors of
the route Cadence resolves.

**The runtime catalog describes what each runtime can do** — its capability
flags, requirements, recommended models, and which provider catalog rows it
represents. The provider option ledger maps provider-specific knobs into
workflow-safe configuration.

**The broker enforces the granted operation surface.** Providers are execution
backends, not principals: the workflow policy decides what an agent may do,
and every brokered call is checked against that grant.

**The harness compiler builds the final prompt/config** for the selected
backend. Headroom (context compression), when enabled for a provider, runs
before the provider call and emits evidence either way.

## Status

All **10 runtimes are available**, and every one of the **2,058 capabilities**
in the catalog has a clear, audited status — none are left in limbo. See the
[Capability Catalog](/harness/capabilities) for the full breakdown.

<Note>
  This doesn't mean every provider does everything. It means each capability
  either works today, or has a clear, dated reason it doesn't yet — blocked by a
  deeda policy, blocked by the vendor, or not offered by the vendor.
</Note>

## Proof, not assertion

A runtime or capability row only counts as available when a cross-provider
proof suite passes for it across all applicable surfaces, with evidence
checked in. The same discipline applies to these docs: the
[Runtimes](/harness/runtimes), [Capability Catalog](/harness/capabilities),
and per-provider pages are generated from the live catalogs, drift-gated in CI.