Coding Harnesses, Adapters, and Agent Protocols
Coding harnesses expose different tools, permission models, session formats, hooks, subagents, context behavior, output events, sandboxes, and completion semantics. A factory that shells out to a CLI may appear provider neutral while silent
A focused view of boundaries, contracts, state, authority, failure paths, and tradeoffs drawn from this chapter.
Reconstruct and defend this chapter’s architecture.
Reconstruct the architecture, name each boundary, and defend the tradeoffs.
Open the source exercise
Draw a factory using a web UI, control plane, outer harness, two interchangeable coding harnesses, a development environment, MCP tools, and one remote A2A specialist. Add an ACP editor client and AG-UI event stream. Mark authentication, authority, lifecycle events, cancellation, evidence, and every place protocol compatibility does not imply trust.
4. Tradeoffs and alternatives
Wrapping a mature harness provides rapid capability and creates adapter work when native behavior changes. Building an inner harness provides control and requires sustained investment in tool execution, context management, model integration, permissions, user experience, and safety.
A thin adapter preserves native features but exposes the control plane to provider differences. A thick adapter normalizes behavior and may erase useful capabilities or create a false lowest-common-denominator abstraction. Preserve native payloads as diagnostic artifacts while translating only the events and commands required by factory contracts.
5. Current Mission Control Implementation
At study commit
d902fae,
Mission Control defines a provider-neutral harness lifecycle, exact capability
manifests, structured results, Execution Manifest bindings, persistent-worker
and remote-sandbox backends, and a codex/v1 adapter. It also separates
executing harnesses from independent verification and publication authority.
The studied Codex and DeepSeek capability manifests declared MCP unsupported, and no first-class production MCP gateway was verified. The evidence also does not establish an ACP, AG-UI, or A2A bridge, cross-harness conformance suite, or complete proof of session resume and behaviorally equivalent substitution. Generic harness architecture was present, while production execution remained unconfigured.
Review this chapter.
Challenge a claim, boundary, missing failure mode, unclear term, or unsupported evidence statement.
- Claim
- Boundary
- Failure
- Evidence