Root cause: lookupPrefix() iterated Go map nondeterministically when
duplicate namespace prefixes mapped to same URI (common in EPUB/OOXML).
Fix: check default namespace first before map iteration.

Performance: String() methods on ListValue, ArrayValue, TupleValue,
RecordValue, TaggedValue used += concatenation (O(n²)). Switched to
strings.Builder. Pre-allocated slices in evalCoreList/Array/Tuple and
XML attribute parsing. Zero-allocation whitespace check for CharData.

Result: Moby Dick EPUB parse 62s → 11.5s (5.4x speedup).

Process: added determinism verification as sprint-executor principle #9
and builtin-developer validation rule #7.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

SKILL.md:
- Rule #7: publish auto-rewrites path deps (new)
- Publishing checklist section (new)
- Registry validator section (new)
- Updated error table with duplicate key error

error_solutions.md:
- TOML duplicate key error (from ailang install bug)
- Publishing with path deps guidance
- Dependency order example

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

… 10 integration gaps

Today's live smoke testing of v0.18.0's M-MOTOKO-EXECUTOR-ADAPTER
surfaced 10 interconnected gaps that prevent trustworthy benchmark
numbers. Three got partial fixes during the day (HealthCheck no-spawn,
MOTOKO_REPO fallback, MOTOKO_HEADLESS, run_summary-before-done reorder)
but root causes remain across both repos. User feedback: "we need it
all I think. lets get to the bottom of the gaps - I think a design
doc process will help."

This sprint sequences the fixes properly:

  Phase 1: Investigation-first for gap #1 (run_summary not reaching
    disk on success path) — debug:checkpoint markers + bisect.
    Non-negotiable; writing a fix without the cause is gambling.

  Phase 2: motoko-side fixes (gap #1 root-cause fix + #6 extension
    visibility + #7 --headless flag + #8 --version mode + #10 TS
    process.exit removal so emission ordering doesn't matter)

  Phase 3: AILANG-side fixes (gap #2 success-criteria fallback to
    thinking.finish_reason + #5 MOTOKO_REPO discovery from wrapper)

  Phase 4: Cross-cutting (gap #4 session_id unification — adapter
    canonical, TS wrapper honors, AILANG runtime emits matching)

  Phase 5: Config layer (gap #3 + #9 cost_rates source-of-truth in
    models.yml.pricing → env-var override of motoko's profile config)

  Phase 6: End-to-end validation — TestEndToEnd_FullResultPopulation
    asserts every Result field; M5 paired-comparison
    motoko-claude-haiku-4-5 vs claude-haiku-4-5 produces real numbers.

Architectural posture: eliminate fragile assumptions at every layer.
Today's adapter assumes things that aren't true (wrapper preserves
session_id, cost_rates configured, run_summary always reaches disk,
loaded_extensions field accurate). After this hardening, none of those
assumptions remain — each replaced with explicit observable contracts.

Net axiom score: +13 (no hard violations). Strong A2 (replayability —
captured runs are fully reproducible), A7 (machines first — Result
fields mechanically reliable), A9 (cost visibility — eliminates $0
reporting gap).

Estimated 3 working days, ~530 LOC including tests, across both repos.
GATING for M5 of v0.18.0 (threshold-measurement) and v0.19.0
M-MOTOKO-EXT-PER-TASK (which needs accurate session_ids + extension
visibility from this hardening).

Cross-references:
- v0.18.0 M-MOTOKO-EXECUTOR-ADAPTER Future Work updated to point at
  this hardening as the trustworthy-numbers prerequisite
- v0.19.0 M-MOTOKO-EXT-PER-TASK Dependencies updated to mark v0.18.1
  as BLOCKING (was just "after local validation")

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…design docs

Phase 6 of v0.18.1 hardening sprint.

Moves both design docs from design_docs/planned/v0_18_1/ to
design_docs/implemented/v0_18_1/ and updates their status headers to
"Implemented (2026-05-08)" with cross-repo commit references.

Adds the v0.18.1 entry to changelogs/v0.10-current.md covering all
five phases:
  - Phase 1 (gap #1): JSONL drain race in TS layer
  - Phase 2 (gaps #6, #7, #8): extensions visibility, --headless, --version
  - Phase 3 (gaps #2, #5): success fallback, MOTOKO_REPO discovery
  - Phase 4 (gap #4): session_id unification
  - Phase 5 (gaps #3, #9): cost rates env-var passthrough

Acceptance gate: 5 of 7 conditions met; the remaining 2 (CostUSD>0
end-to-end + smoke success) blocked on a separate Bedrock validation
issue (extension tool names with `/` fail Anthropic's
^[a-zA-Z0-9_-]{1,128}$ pattern). The pricing env-var plumbing is
verified by unit tests; live smoke needs the extension fix downstream.

LOC tally: ~80 AILANG-side + ~250 motoko-side + 11 new tests across
both repos, in ~6 hours wall-clock vs the 3-day plan estimate.

Sprint retrospective: investigation-first paid off — the 12 debug:
checkpoint markers in Phase 1 directly identified the silent-exit
point as the TS process.exit-on-done race, which would have been
maddening to find by code-reading alone. The resulting fix was tiny
(~25 LOC across 2 TS files) but unblocked everything downstream.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Arni's PR #6 review (with Opus 4.6's analysis) flagged that motoko_agent's
ailang.toml/ailang.lock had absolute /Users/mark/dev/... paths baked in,
making the lockfile non-portable and breaking any external clone.

The actual fix shipped on motoko-bisect-gap1 / PR #7 (commit f105af2):
swap path-based deps for registry versions — same packages, all already
published.

This commit adds two things to extension-packages.md so future readers
won't fall into the same trap:

1. A note immediately after the host ailang.toml example explaining when
   to use registry vs path — and warning that path is a dev-loop tool,
   not a release-ready format.

2. A new "Path vs registry checklist" section with concrete jq/ailang
   commands to verify the lockfile before opening a PR.

The example ailang.toml now uses fully-qualified registry refs
("sunholo/motoko_ext_abi" = "1.0.0") to match what users will actually
write — the previous bare-name form ("motoko-ext-abi") didn't include
the registry namespace.

Refs: PR arniwesth/motoko_agent#6 (review by arniwesth + Opus 4.6 analysis)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

The Typical usage block in std/ai.stepWithStream's docstring showed:

  let render = \chunk ->
    match chunk { ... }

which is doubly wrong:
  - AILANG lambda syntax is \x. body, not \x -> body (the latter is the
    type-arrow + match-arm syntax)
  - match-in-lambda hits a known parser bug (see
    design_docs/planned/v0_13_0/m-dx-match-in-hof-block-lambda.md)

Replaced with the top-level-func pattern that examples/runnable/
ai_streaming.ail actually uses. Tracks reality and demonstrates the
parser-bug workaround in one place.

Caught while wiring stepWithStream into motoko_agent
(arniwesth/motoko_agent PR #7) — the original syntax doesn't compile.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>