v0.2.0 MCP Server & Agent-to-Agent Interface

Tether as a subagent for the harness you already use (Claude Code, Codex, Cursor, Gemini CLI, Copilot): MCP server, JSON output and exit codes (#46). See Use Tether Inside Your Harness.

Features

• MCP server (optional extra, pip install "tether-sdk[mcp]"; without it tether mcp warns and exits 1): tether mcp over stdio with tether_run|status|wait|read|send|list|stats|query.
• --json on run, pipeline, status, list, read, wait, send, stats; stable schema v: 1.
• Exit codes: 0 completed, 1 usage, 2 waiting for input, 3 gate failed, 4 max steps, 5 worker error. Failure text now goes to stderr.
• Harness(output_schema=...) / --output-schema, --result-file (JSON Schema subset enforced as a done gate), tether events <id> [--follow].

Fixes

• Worker errors keep the exception type and store the traceback as a tool_error turn (#41).
• ollama no longer silently substitutes an installed model on 404; it fails with the installed list. Opt back in with TETHER_OLLAMA_FALLBACK=1 (#21).

Behavior changes

• tether wait now exits non-zero when a session failed or needs input (it always returned 0 before).