v1.13.16-xml-parser: Anthropic <invoke> support + unknown-tool recovery hints

Two-part fix for the model-emitted XML drift the v1.13.15-codecontext-synth
investigation surfaced (1 raw <invoke> leak observed out of 190 qwen3.6
turns — qwen3.6-35b-a3b-mxfp4 drifts to the Anthropic format when prompted
as an Architect-style agent because Claude Code documentation in its
pre-training corpus uses that shape).

## Parser extension

xml-parser.ts now recognizes BOTH XML tool-call flavors:

  - Qwen/Hermes:   <tool_call><function=NAME>...<parameter=K>V</parameter>...</function></tool_call>
  - Anthropic:     <invoke name="NAME"><parameter name="K">V</parameter></invoke>

Both route through the same synthetic-id xml_call_${idx} ToolCall path.
extractToolCallBlocks() and partialXmlOpenerStart() handle both openers
(<tool_call> and <invoke...) so partial buffers don't get prematurely
flushed during streaming.

The existing Qwen parser was tightened to tolerate whitespace around `=`
(<function = name>, <parameter = key>...) so a stray space doesn't get
absorbed into the function name. Name capture is non-whitespace,
non-`>`.

## Unknown-tool recovery hint

New tool-suggestions.ts exports levenshtein() + suggestToolName() +
formatUnknownToolError(). When tool-phase.ts:executeToolCall receives a
toolCall.name that isn't in TOOLS_BY_NAME, the error returned to the
model now includes a "Did you mean: X?" hint based on Levenshtein
distance ≤3 or substring match against Object.keys(TOOLS_BY_NAME).
Targets the qwen3.6 drift to read_file → suggest view_file. Applies to
all unknown tool names, not just <invoke>-derived ones — at the
dispatch layer we no longer know which format produced the call, and
the extra signal is harmless for Qwen-derived calls.

## Test coverage

xml-parser.test.ts: 46 tests, all green. Covers both parsers
(well-formed, malformed, multi-parameter, nested-content), the
partial-opener detector for both flavors, the unified extraction
helper, and the unknown-tool error formatter.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes per release tag. Most recent on top, ordered by tag creation date (which matches the git history). Tag names follow `vMAJOR.MINOR.PATCH-slug` — the slug describes what shipped, so the tag name alone is enough to recall the batch.
 
+## v1.13.16-xml-parser — 2026-05-22
+
+Two-part fix for the model-emitted XML drift the v1.13.15 investigation surfaced. **Parser extension:** `xml-parser.ts` now recognizes the Anthropic `<invoke name="…"><parameter name="…">…</parameter></invoke>` shape alongside the existing Qwen/Hermes `<tool_call><function=…>…</function></tool_call>` shape. qwen3.6-35b-a3b-mxfp4 drifts to the Anthropic format when prompted as an Architect-style agent (Claude Code documentation in its pre-training corpus). Both formats route through the same synthetic-id `xml_call_${idx}` ToolCall path. The existing Qwen parser was tightened to tolerate whitespace around `=` (`<function = name>` shape) so a stray space doesn't get absorbed into the function name. **Unknown-tool recovery hint:** new `tool-suggestions.ts` exports `levenshtein()` + `suggestToolName()` + `formatUnknownToolError()`. When the dispatcher (`tool-phase.ts:executeToolCall`) receives an unknown tool name, the error returned to the model includes a "Did you mean: X?" hint based on Levenshtein distance ≤3 or substring match against `Object.keys(TOOLS_BY_NAME)`. Targets the qwen3.6 drift to `read_file` → suggest `view_file`. Test coverage in `xml-parser.test.ts` (46 tests, all green) covers both parsers, the partial-opener detector for both flavors, the unified extraction helper, and the new error formatter.
+
 ## v1.13.15-codecontext-synth — 2026-05-22
 
 Forced second-inference synthesis pass for codecontext overview-class tools (`get_codebase_overview`, `get_framework_analysis`, `get_semantic_neighborhoods`). After the tool result lands, the pipeline expands the truncated head via in-process `readTruncation`, extracts referenced file paths from the full content, auto-fetches top-N files + project docs (BOOCHAT.md, AGENTS.md, *roadmap*.md, CONTEXT.md) under a 32k-token budget with explicit drop-priority order, then streams a synthesis turn that replaces the recursive `runAssistantTurn`. The 32k truncated head still ships to the synth model (token-budget contract preserved); the expansion is reference-extraction-only. Falls through to recursion on timeout (90s), model error, or non-2xx; user-abort marks the synth message `status='failed'` and re-throws (the outer abort handler operates on the parent turn's message, not the new synth row — without explicit marking, the row would sit `streaming` until the 5-min sweeper, tripping the 60s stale-stream banner). Adds `'synthesis'` to `message_parts.kind` CHECK constraint via `DROP CONSTRAINT IF EXISTS` + `DO $$ pg_constraint` idempotency-guarded re-add. Smokes #1, #2, #6 all clean; smokes #3–#5 are content-quality checks for UI review.