nexus-legal 0.1.1

Official Python SDK for the Nexus Legal API v1 — multi-jurisdictional legal analysis with certainty locks, async jobs, signed webhooks, organizations and sub-keys.

nexus-legal

Official Python SDK for the Nexus Legal API v1 — multi-jurisdictional legal analysis with defensible certainty locks, vector case-law search, async jobs, signed webhooks, organizations and sub-keys.

pip install nexus-legal

Requires Python ≥ 3.9.

Quick start

import os
from nexus_legal import NexusClient

nexus = NexusClient(api_key=os.environ["NEXUS_API_KEY"])

result = nexus.analyze(
    text="Por el presente contrato, el arrendador cede el uso…",
    jurisdiction="ES",
    legal_branch="civil",
)

print(result["analysis"])
print("Rate limit remaining:", result["rate_limit"]["remaining"])

Get an API key at /developers. Full docs at /developers/docs.

Features

• Synchronous — built on requests. Async (httpx) coming in a future release.
• Auto idempotency — every POST carries an auto-generated Idempotency-Key (UUID4) reused across retries → no double-charge.
• Smart retries — 429 / 5xx with exponential backoff + jitter, honoring Retry-After.
• Typed errors — RateLimitError, InsufficientCreditsError, IdempotencyConflictError, ValidationError, AuthenticationError, ServerError, TimeoutError.
• Rate-limit telemetry — every response exposes result["rate_limit"].
• Audit-trail parser — extract_audit_trail() returns a structured TypedDict without any YAML dependency.
• Webhook signature verification — verify_webhook_signature() for incoming HMAC-signed deliveries.

API surface

nexus = NexusClient(
    api_key="nlk_...",
    base_url="https://nexusquantum.legal",   # default
    timeout=120.0,                            # seconds
    max_retries=3,
    auto_idempotency=True,
)

# Sync
nexus.analyze(text=..., jurisdiction="ES", legal_branch="civil")
nexus.analyze_batch(documents=[...], concurrency=5)

# Sandbox (no credits)
nexus.sandbox.analyze(sample="providencia_aeat")
nexus.sandbox.metadata()

# Case-law search
nexus.jurisprudencia.search(query="...", jurisdiction="ES", top_k=5)

# Catalogs and usage
nexus.jurisdictions.list()
nexus.usage.get(from_="2026-04-01", to="2026-05-01", granularity="day")
nexus.usage.csv(from_="2026-04-01", to="2026-05-01")

# Async jobs
job = nexus.jobs.create(kind="analyze", payload={"text": ..., "jurisdiction": "ES"})
snap = nexus.jobs.get(job["jobId"])
final = nexus.jobs.run(kind="analyze", payload={...})   # poll helper

# Webhooks
wh = nexus.webhooks.create(url="https://example.com/hook", events=["analysis.completed"])
print("Secret:", wh["secret"])   # shown once

# Organizations + sub-keys
org = nexus.organizations.create(name="Mi Despacho LATAM")
sk  = nexus.organizations.create_key(org["organization"]["id"], child_label="Despacho Vázquez")

Error handling

from nexus_legal import (
    InsufficientCreditsError,
    RateLimitError,
    ValidationError,
)

try:
    nexus.analyze(text=text, jurisdiction="ES")
except InsufficientCreditsError as e:
    print(f"Need {e.required}, have {e.balance}")
except RateLimitError as e:
    time.sleep(e.retry_after)
except ValidationError as e:
    print(f"Bad request: {e}")

Webhook signature verification

import os
from nexus_legal import verify_webhook_signature
from flask import Flask, request

app = Flask(__name__)

@app.post("/nexus-webhook")
def webhook():
    raw = request.get_data()                       # bytes, pre-parse
    sig = request.headers.get("X-Nexus-Signature")
    if not verify_webhook_signature(
        raw_body=raw,
        signature=sig,
        secret=os.environ["WEBHOOK_SECRET"],
    ):
        return ("invalid signature", 401)
    payload = request.get_json()
    # ...

Audit-trail parsing

from nexus_legal import extract_audit_trail

trail = extract_audit_trail(result["analysis"])
if trail and trail["levels_emitted"].get("L5-C", 0) > 0:
    # Critical contractual risk — escalate to human reviewer
    ...

The parser handles levels_emitted, review_flags, modules_active, kill_switches_triggered, rag_sources, executive_summary and exposes the raw YAML in trail["raw"] for callers who want to re-parse with PyYAML.

Versioning

This SDK targets API v1.x and follows SemVer:

• MAJOR — drops support for an API breaking change.
• MINOR — new endpoints, new fields, new options.
• PATCH — bug fixes, doc improvements.

See the API changelog.

License

MIT — see LICENSE.

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Built by Nexus Legal. Questions? Email [e-mail].