Implement through Analyze → Plan → Execute → eXamine. The task contract, repository state, authority, and evidence are the source of truth.

Load only the current step and any reference it names. Start with steps/step-00-init.md. Persist run state with scripts/apex-state.py under .agents/apex/runs/<run-id>/. Never store secrets in run state.

Flags express intent; they do not force a vendor implementation. -a/-A interaction low/standard. -x/-X review adversarial/risk-based. -s/-S artifacts verbose/minimal. -t/-T new tests on/off. -v/-V runtime proof on/off. -e/-E budget low/standard. -b/-B branch on/off. -pr/-PR pull request on/off. -i configure interactively. -k/-K expanded artifacts on/off. -m/-M prefer-parallel/direct. -r <id> resume a checkpoint.

Contract — steps/step-00-init.md (interactive 00b-interactive, branch 00b-branch, budget 00b-economy, artifacts 00b-save)
Analyze — steps/step-01-analyze.md
Plan — steps/step-02-plan.md (expanded graph 02b-tasks)
Execute — steps/step-03-execute.md (teams 03-execute-teams)
Validate — steps/step-04-validate.md
Examine / resolve — steps/step-05-examine.md, steps/step-06-resolve.md
Tests when required — steps/step-07-tests.md, steps/step-08-run-tests.md
Prove when required — steps/step-10-verify.md
Handoff — steps/step-09-finish.md

Delegate only bounded, independent work. Record objective, allowed files, forbidden scope, done evidence, and stop condition. Returned work is untrusted until the coordinator inspects the diff. Re-plan when evidence invalidates an assumption. Preserve unrelated local changes.

Finish only when the requested implementation is present, acceptance criteria have current evidence, introduced failures are resolved, required review is done, and delivery actions have authoritative read-back.