CallLens

Open-source conversation intelligence and behavioral evaluation powered by LangGraph.

Upload a call. CallLens transcribes it, reconstructs the conversation, measures deterministic communication metrics, evaluates semantic behaviors against configurable rubrics, verifies the supporting evidence, and produces explainable conversation intelligence.

CallLens turns raw conversations — recordings or transcripts — into structured, evidence-backed behavioral intelligence: diarized transcripts, talk-time and pace metrics, longitudinal sentiment, topics, opportunity/risk detection, and per-representative analytics, all scored against declarative, versioned rubrics.

Every semantic score is evidence-backed. Never just Discovery: 8/10. Instead:

Discovery: 8.7/10
Confidence: 0.91

Evidence:
  04:32  Representative asks customer about their current operational bottleneck.
  05:17  Representative asks about business impact.
  07:02  Customer explains delivery delays.

Missing behavior:
  Representative never established urgency or implementation timeframe.

Users click a timestamp and the audio player jumps to that exact moment.

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Why it exists

Most call-scoring tools either (a) send the whole transcript to an LLM and ask for a number, or (b) count keywords. CallLens does neither:

• Multi-stage scoring — candidate evidence extraction → deterministic verification → rubric scoring → consistency check → confidence gate → bounded re-judge. Never a single "score this transcript" prompt.
• Deterministic where possible, semantic only where needed — talk time, wpm, interruptions, turns, and silences are pure Python. LLMs are used for reasoning: sentiment, topics, intent, behavior, coaching.
• Provider isolation — a speech abstraction (ElevenLabs today) and an LLM abstraction (OpenAI / Anthropic / any OpenAI-compatible endpoint), so nothing is hardwired to one vendor.
• Auditable by design — every analysis records model, prompt, rubric, and pipeline versions.

Architecture

flowchart TD
    A[Audio / Transcript] --> B[Ingestion]
    B --> C[ElevenLabs STT + Diarization]
    C --> D[Transcript Normalization]
    D --> E[LangGraph]
    E --> F[Deterministic Metrics]
    E --> G[Semantic Analysis]
    G --> H[Sentiment]
    G --> I[Topics]
    G --> J[Intents]
    F --> K[Evidence Verification]
    H --> K
    I --> K
    J --> K
    K --> L[Confidence Gate]
    L -->|sufficient| M[Report]
    L -->|insufficient| N[Bounded Re-score]
    N --> K

See docs/ARCHITECTURE.md, docs/LANGGRAPH.md, and docs/DATA_MODEL.md.

Quick start

Docker (recommended)

cp .env.example .env
docker compose up

• API + OpenAPI docs: http://localhost:8000/docs
• Dashboard: http://localhost:3000

No API keys are required to try it: without ELEVENLABS_API_KEY the speech provider and reasoning LLM fall back to deterministic offline mocks, so the full pipeline (transcribe → metrics → evidence-backed rubric scoring → coaching) runs end to end.

Local (Python)

python -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"

# Analyze a transcript (offline, deterministic)
calllens analyze sample.txt

# Start the API server
calllens server

# Run the evaluation harness
calllens eval run

Frontend

cd apps/web
npm install
NEXT_PUBLIC_API_URL=http://localhost:8000 npm run dev

CLI

calllens analyze call.mp3
calllens analyze call.mp3 --rubric consultative_sales --output report.json
calllens rubric list
calllens rubric validate ./my_rubric.yaml
calllens eval run
calllens server

Python SDK

import asyncio
from calllens import CallLens


async def main():
    async with CallLens(base_url="http://localhost:8000") as client:
        call = await client.calls.upload("sales-call.mp3")
        await call.analyze(rubric="consultative_sales")
        report = await call.report()
        print(report["overall_score"], report["confidence"])


asyncio.run(main())

REST API (subset)

POST   /api/v1/calls                     upload a recording or transcript
GET    /api/v1/calls
GET    /api/v1/calls/{id}
POST   /api/v1/calls/{id}/analyze
GET    /api/v1/calls/{id}/analysis       the evidence-backed CallReport
GET    /api/v1/calls/{id}/transcript
DELETE /api/v1/calls/{id}                privacy/retention deletion
POST   /api/v1/rubrics                   register a declarative rubric
GET    /api/v1/rubrics
POST   /api/v1/rubrics/validate
GET    /api/v1/reps/{id}/analytics
POST   /api/v1/evals/run

Interactive docs at /docs.

Rubrics

Rubrics are declarative and versioned YAML documents. The engine itself is generic — sales is just the first bundled rubric. Bring your own: customer support, recruitment, collections, insurance, real estate, customer success, interviews, AI voice agents.

name: consultative_sales
version: "1.0"
dimensions:
  rapport:
    label: Rapport
    weight: 0.08
  discovery:
    label: Problem Discovery
    weight: 0.16

Dimension weights must sum to 1.0. See rubrics/ and docs/custom-rubrics.

Providers

Layer	Provider	Config
Speech (STT/TTS)	ElevenLabs Scribe v2	ELEVENLABS_API_KEY, ELEVENLABS_STT_MODEL
Reasoning LLM	OpenAI	LLM_PROVIDER=openai, OPENAI_API_KEY, LLM_MODEL
Reasoning LLM	Anthropic	LLM_PROVIDER=anthropic, ANTHROPIC_API_KEY, LLM_MODEL
Reasoning LLM	Any OpenAI-compatible endpoint	LLM_PROVIDER=compatible, COMPATIBLE_BASE_URL, COMPATIBLE_API_KEY
Reasoning LLM	Offline mock (default)	LLM_PROVIDER=mock

All tests and CI run against mocks — no paid API calls.

Example: live analysis with real providers

Wire both providers in .env and analyze an actual recording:

# .env — speech + reasoning
ELEVENLABS_API_KEY=sk_...
ELEVENLABS_STT_MODEL=scribe_v2

# Any OpenAI-compatible endpoint, e.g. Melious (https://api.melious.ai/v1)
LLM_PROVIDER=compatible
COMPATIBLE_BASE_URL=https://api.melious.ai/v1
COMPATIBLE_API_KEY=sk-mel-...
LLM_MODEL=gpt-oss-120b

Then run the full pipeline on a recording — it must be a pre-recorded call file (MP3/WAV), but you can synthesize one if you don't have a recording handy:

# Option A — you have a recording: transcribe + analyze it live
# (Scribe v2 STT → metrics → evidence-backed scoring → coaching)
calllens analyze call.mp3 --rubric consultative_sales --output report.json

# Option B — no recording? Synthesize a two-speaker sample call with ElevenLabs TTS
python examples/generate_sample_call.py   # → sample_call.mp3
calllens analyze sample_call.mp3 --rubric consultative_sales --output report.json

# Both write the evidence-backed report (scores + timestamped evidence + coaching)
# to report.json; omit --output to print it to stdout.

The compatible endpoint must support OpenAI JSON-schema structured outputs (response_format: {type: "json_schema"}) — the pipeline's structured_completion depends on it. Not every model on every gateway does; e.g. gpt-oss-120b on Melious works, while several others (GLM, Kimi, DeepSeek v4 on Melious) reject schema mode. Probe with a small structured call before committing to a model.

MCP / MCPize

CallLens ships an MCP server exposing analyze_transcript, score_dimension, and list_rubrics, deployable on MCPize:

mcpize analyze && mcpize doctor && mcpize deploy

Local stdio:

pip install -r requirements.txt
python mcp-server/server.py

Evaluation

| Dimension | MAE | Correlation |
|-----------|-----|-------------|
| Discovery | .61 | .88         |
| Rapport   | .74 | .81         |

The harness (calllens.evals) runs the full pipeline over a 13-scenario synthetic dataset (excellent seller, poor seller, weak discovery, angry customer, multilingual, …) and reports MAE, RMSE, correlation, and evidence precision/recall against human-quality labels.

Roadmap

See docs/ROADMAP.md. Highlights: Supabase auth/RLS and object storage, async job backends (Redis/SQS), GraphQL dashboard queries, live-call mode, AI role-play mode, per-representative trends, drift monitoring.

Security & privacy

• API keys are environment-only; nothing is ever committed, logged, or exposed to the browser.
• Call recordings are treated as sensitive: tenant isolation, private/signed storage, deletion and configurable retention.
• Complete transcripts are never logged by default.
• See SECURITY.md and docs/ARCHITECTURE.md.

License

MIT © Yabloko Labs