A graph-based implementation agent. Plans, implements, and runs build + tests in a bounded fix-loop until verified. Designed to be delegated to by the Sisyphus agent.

Coder is a graph agent: its workflow is defined declaratively in graph.yaml, with verification and the implement-fix loop enforced as graph edges rather than prose.

Workflow

analyze_request (llm + output_schema)   plan + complexity extraction
        ↓
route_complexity (script)               opt-out approval gate (complexity ≥ 7)
        ↓
gate_approval (approval, optional)
        ↓
implement (llm + fs tools)              actual file edits
        ↓
verify_build (script)
        ↓
verify_tests (script)
        ↓
fix_loop_gate (script)                  back-edge to implement (bounded)
        ↓
end_success / end_rejected / end_failure

End nodes emit one of three sentinel outcomes for the caller:

CODER_COMPLETE — build and tests passed.
CODER_REJECTED — user rejected the plan at the approval gate.
CODER_FAILED — fix-loop exhausted; build/tests still failing.

Tuning

The agent's project_dir is exposed via the standard variables: block, so it accepts the runtime override flag:

# Invoke from inside the project (project_dir defaults to ".")
cd /path/to/your/project
loki -a coder "Add a foo() function..."

# Or invoke from anywhere with an explicit override
loki -a coder --agent-variable project_dir /path/to/your/project "Add..."

graph.yaml initial_state exposes:

max_fix_attempts (default 3) — fix-loop budget before end_failure.

Environment overrides honored by the script nodes:

BUILD_CMD — skip project-type detection for the build/check command.
TEST_CMD — skip detection for tests.
CODER_AUTOAPPROVE=1 — bypass the approval gate (for non-interactive runs where complexity might trip the gate).

Pro-Tip: IDE MCP Server

Modern IDEs (JetBrains, VS Code, Cursor, Zed, etc.) expose MCP servers that let LLMs use IDE tools directly. To wire one in, edit graph.yaml:

mcp_servers:
  - your-ide-mcp-server

global_tools:
  # Keep read-only fs tools for files outside the IDE project
  - fs_read.sh
  - fs_grep.sh
  - fs_glob.sh
#  - fs_write.sh
#  - fs_patch.sh
  - execute_command.sh

Then add the MCP server's write/patch tools to the implement node's tools: whitelist.