Replace all strings.ToLower usage with ASCII case-insensitive matching
(hasASCIIPrefixFoldAt, indexASCIIFold, hasDSMLPrefix) to prevent slice
bounds errors when Unicode characters change byte length after case
folding (e.g., Turkish İ U+0130 → i + combining dot: 2 bytes → 3 bytes).
Root cause: code created a strings.ToLower(text) copy, found byte
positions in that copy, then used those positions to slice the
original text — byte offsets that were valid in the lowercased copy
became out-of-bounds in the original when case folding changed byte
lengths.
Files changed:
- toolcalls_scan.go: remove 5 lower usages, add hasDSMLPrefix
- toolcalls_parse_markup.go: remove 3 lower usages, add indexASCIIFold
- toolcalls_markup.go: SanitizeLooseCDATA lower removal
- toolcalls_parse.go: updateCDATAStateForStrip lower removal
- tool_prompt.go: align DSML pipe characters with tool call spec
- tool_prompt_test.go: fix pre-existing test character mismatch
- Add shared ToolMarkupTag scanner (toolcalls_scan.go) replacing hardcoded alias tables
- Support DSML collapsed tag names (<DSMLtool_calls>, <DSMLinvoke>, <DSMLparameter>)
- Parse JSON literal values from parameter bodies (123→number, true→bool, null)
- Recover unclosed CDATA in final parse/flush via SanitizeLooseCDATA
- Align Go and Node implementations (scanToolMarkupTagAt, findMatchingToolMarkupClose)
- Reject bare <invoke> as unsupported syntax, only tool_calls wrapper triggers tool path
- Update API.md and toolcall-semantics.md documentation
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
