The Python code examples were accessing nested error.kind like envelope['error']['kind'],
but v1.0 emits flat envelopes with error as a STRING and kind at top-level.
Updated:
- Table header: now shows actual v1.0 shape {error: "...", kind: "...", type: "error"}
- match statement: switched from envelope.get('error',{}).get('kind') to envelope.get('kind')
- All ClawError raises: changed from envelope['error']['message'] to envelope.get('error','')
because error field is a STRING in v1.0, not a nested object
- Added inline comments on every error case noting v1.0 vs v2.0 difference
- Appendix: split into v1.0 (actual/current) and v2.0 (target after FIX_LOCUS_164)
The code examples now work correctly against the actual binary.
This was active misdocumentation (P0 severity) — the Python examples would crash
if a consumer tried to use them.
Cycle #29 dogfood found a real pinpoint: cross-mode exit code divergence.
## The Pinpoint
Dogfooding the CLI revealed that unknown subcommand errors return different
exit codes depending on output mode:
$ python3 -m src.main nonexistent-cmd # exit 2
$ python3 -m src.main nonexistent-cmd --output-format json # exit 1
ERROR_HANDLING.md documented the exit-code contract (1=parse, 2=timeout)
but did NOT explicitly state the contract applies only to JSON mode. Text
mode follows argparse defaults (exit 2 for any parse error), which
violates the documented contract when interpreted generally.
A claw using text mode with 'claw nonexistent' would see exit 2 and
misclassify as timeout per the docs. Real protocol contract gap, not
implementation bug.
## Classification
This is a DOCUMENTATION gap, not a behavior bug:
- Text mode follows argparse convention (reasonable for humans)
- JSON mode normalizes to documented contract (reasonable for claws)
- The divergence is intentional; only the docs were silent about it
Fix = document the divergence explicitly + lock it with tests.
NOT fix = change text mode exit code to 1 (would break argparse
conventions and confuse human users).
## Documentation Changes
ERROR_HANDLING.md:
1. Added IMPORTANT callout in Quick Reference section:
'The exit code contract applies ONLY when --output-format json is
explicitly set. Text mode follows argparse conventions.'
2. New 'Text mode vs JSON mode exit codes' table showing exact divergence:
- Unknown subcommand: text=2, json=1
- Missing required arg: text=2, json=1
- Session not found: text=1, json=1 (app-level, identical)
- Success: text=0, json=0 (identical)
- Timeout: text=2, json=2 (identical, #161)
3. Practical rule: 'always pass --output-format json'
## Tests Added (5)
TestTextVsJsonModeDivergence in test_cross_channel_consistency.py:
1. test_unknown_command_text_mode_exits_2 — text mode argparse default
2. test_unknown_command_json_mode_exits_1 — JSON mode contract normalized
3. test_missing_required_arg_text_mode_exits_2 — same for missing args
4. test_missing_required_arg_json_mode_exits_1 — same normalization
5. test_success_path_identical_in_both_modes — success exit identical
These tests LOCK the expected divergence so:
- Documentation stays aligned with implementation
- Future changes (either direction) are caught as intentional
- Claws trust the docs
## Test Status
- 217 → 222 tests passing (+5)
- Zero regressions
## Discipline
This cycle follows the cycle #28 template exactly:
- Dogfood probe revealed real friction (test said exit=2, docs said exit=1)
- Minimal fix shape (documentation clarification, not code change)
- Regression guard via tests
- Evidence-backed, not speculative
Relationship to #181:
- #181 fixed env.exit_code != process exit (WITHIN JSON mode)
- #29 clarifies exit code contract scope (ONLY JSON mode)
- Both establish: exit codes are deterministic, but only when --output-format json
---
Classification (per cycle #24 calibration):
- Red-state bug? ✗ (behavior was reasonable, docs were incomplete)
- Real friction? ✓ (docs/code divergence revealed by dogfood)
- Evidence-backed? ✓ (test suite probed both modes, found the gap)
Source: Jobdori cycle #29 proactive dogfood — in response to Clawhip nudge
for pinpoint hunting. Found that text-mode errors return exit 2 but
ERROR_HANDLING.md implied exit 1 was the parse-error contract universally.
Cycle #22 ships documentation that operationalizes cycles #178–#179.
Problem context:
After #178 (parse-error envelope) and #179 (stderr hygiene + real error message),
claws can now build a unified error handler for all 14 clawable commands.
But there was no guide on how to actually do that. Operators had the pieces;
they didn't have the pattern.
This file changes that.
New file: ERROR_HANDLING.md
- Quick reference: exit codes + envelope shapes (0=success, 1=error, 2=timeout)
- One-handler pattern: ~80 lines of Python showing how to parse error.kind,
check retryable, and decide recovery strategy
- Four practical recovery patterns:
- Retry on transient errors (filesystem, timeout)
- Reuse session after timeout (if cancel_observed=true)
- Validate command syntax before dispatch (dry-run --help)
- Log errors for observability
- Error kinds enumeration (parse, session_not_found, filesystem, runtime, timeout)
- Common mistakes to avoid (6 patterns with BAD vs GOOD examples)
- Testing your error handler (unit test examples)
Operational impact:
Orchestration code now has a canonical pattern. Claws can:
- Copy-paste the run_claw_command() function (works for all commands)
- Classify errors uniformly (no special cases per command)
- Decide recovery deterministically (error.kind + retryable + cancel_observed)
- Log/monitor/escalate with confidence
Related cycles:
- #178: Parse-error envelope (commands now emit structured JSON on invalid argv)
- #179: Stderr hygiene + real message (JSON mode silences argparse, carries actual error)
- #164 Stage B: cancel_observed field (callers know if session is safe for reuse)
Updated CLAUDE.md:
- Added ERROR_HANDLING.md to 'Related docs' section
- Now documents the one-handler pattern as a guideline
No code changes. No test changes. Pure documentation.
This completes the documentation trail from protocol (SCHEMAS.md) →
governance (OPT_OUT_AUDIT.md, OPT_OUT_DEMAND_LOG.md) → practice (ERROR_HANDLING.md).
