Files
transcriptor-ai/internal/asr/leak.go
T
sttlab-tech 3525e6b8fb initial commit: live meeting transcription pipeline
Go orchestrator: spawns audiotee for capture (system audio + mic, two
tracks), segments with an energy-threshold VAD, transcribes each segment
via qwen-asr (subprocess per segment, vendored as a pinned git submodule
in third_party/qwen-asr), and serves the live transcript over SSE while
also writing it durably to a text file. Includes a glossary/prompt-leakage
guard (internal/asr/leak.go) that discards a segment if the model echoes
the biasing prompt instead of transcribing.

cmd/transcriptor-ai is the main orchestrator; cmd/transcript-tail is a
minimal terminal SSE client. See CLAUDE.md for the full architecture and
the reasoning behind each choice (Go over Python/Swift/Rust, SSE over
WebSocket, why the VAD is a hand-rolled heuristic, etc).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-09 13:18:57 +02:00

62 lines
2.1 KiB
Go

package asr
import (
"strings"
"unicode"
)
// looksLikePromptLeak reports whether text appears to be the model echoing
// the --prompt biasing content back verbatim instead of genuinely
// transcribing the segment's audio — a known failure mode of
// prompt-conditioned generation, confirmed via real testing against
// qwen_asr (see transcriptor-ui/CLAUDE.md, "Glossary prompt-leakage bug"):
// a whole segment came back as literally the glossary terms, twice, on two
// separate 5-minute test runs, even after switching to the tool's
// recommended "Preserve spelling: ..." prompt framing (which reduces but
// does not eliminate the risk).
//
// Heuristic: if most of text's words also appear among prompt's words, and
// there are enough of them to rule out a legitimate short mention of one
// or two glossary terms in real speech, treat it as a leak. Both observed
// real leaks were near-total reproductions of the prompt's term list, so a
// strict threshold (80% word overlap, at least 4 words) catches them
// without plausibly false-flagging a normal sentence that happens to
// mention "Claude" or "Mistral" once — normal speech has enough other
// words to keep the overlap ratio well below that.
func looksLikePromptLeak(text, prompt string) bool {
if prompt == "" || text == "" {
return false
}
textWords := normalizeWords(text)
if len(textWords) < 4 {
return false
}
promptWords := wordSet(normalizeWords(prompt))
matched := 0
for _, w := range textWords {
if promptWords[w] {
matched++
}
}
return float64(matched)/float64(len(textWords)) >= 0.8
}
// normalizeWords lowercases and splits on anything that isn't a letter or
// digit — unicode.IsLetter (not an ASCII-only check) so accented
// characters (French: é, è, ï, ç, ...) stay part of their word instead of
// being split into fragments.
func normalizeWords(s string) []string {
return strings.FieldsFunc(strings.ToLower(s), func(r rune) bool {
return !unicode.IsLetter(r) && !unicode.IsDigit(r)
})
}
func wordSet(words []string) map[string]bool {
set := make(map[string]bool, len(words))
for _, w := range words {
set[w] = true
}
return set
}