SeenRelay Python client

Measure and avoid redundant expensive validation.

The base package is standard-library-only. It places SeenRelay CHECK around repeated source-backed validation while preserving the application's original validation by default, and it also provides a network-free Zero-State path for eligible caller-owned reuse.

Client 0.2.10 adds provider-independent Zero-State for explicit read-only validation: in-flight/local reuse, caller-owned private L1, and source-native conditional validation before the authoritative fallback. Ambient framework adapters remain shadow-only by default, and the hosted CHECK/OBSERVE protocol is unchanged. The direct Firecrawl SDK shadow adapter remains JavaScript / TypeScript-only.

Shared CHECK assurance

seenrelay_assurance evaluates additive CHECK evidence without treating it as truth. The multi-signal retained-reuse preset requires at least two observer keys, two cryptographic continuity keys, and two reuse-independence buckets, plus matching value fingerprints and acceptable freshness.

from seenrelay_assurance import multi_signal_retained_reuse_policy

reuse = multi_signal_retained_reuse_policy({"maxAgeSeconds": 300})

Using the policy is explicit caller opt-in. Multiple keys and buckets make trivial single-origin poisoning harder; they do not prove independent real-world actors or truth. High-consequence validation should still require authoritative source confirmation under the application's own policy.

Deterministic coordinates

seenrelay_coordinates keeps local call coordinates separate from shared source-backed fact descriptors.

from seenrelay_coordinates import (
    mcp_tool_coordinate,
    openapi_operation_coordinate,
    json_pointer_fact,
)

local_call = mcp_tool_coordinate(
    "catalog-prod",
    "catalog.read",
    {"id": 42},
)

api_call = openapi_operation_coordinate(
    "catalog-api",
    "getProduct",
    {"id": 42},
)

fact = json_pointer_fact(
    "Product 42 stock",
    "availability.current",
    "https://api.example.com/products/42",
    "/stock",
)

MCP/OpenAPI coordinates are local repetition keys only. Shared fact builders require a stable source-native locator. Prefer fragmentation to guessed semantic convergence.

Python Zero-State for fleet-local reuse

seenrelay_zero_state adds no hosted operation and performs no SeenRelay network call by itself. It is for applications that control an eligible read-only validation path and want the cheapest caller-owned path first.

from seenrelay_zero_state import SeenRelayZeroState, fresh_result

edge = SeenRelayZeroState(local_max_age_ms=5_000)

value = await edge.guard(
    coordinate={"tool": "catalog.read", "arguments": {"id": 42}},
    validate=lambda conditional_headers: fetch_catalog(42, conditional_headers),
)

The authoritative validator remains the fallback. A positive local/private freshness window is explicit caller policy; the default completed-result TTL is zero. A retained ETag or Last-Modified value may still be used for conditional source confirmation when completed-result reuse is disabled.

For caller-owned private L1 across workers or restarts, supply both a store and a codec. The backing store receives only an opaque SHA-256 coordinate key and a sealed payload.

pip install 'seenrelay[crypto]'

import os
from seenrelay_zero_state import SeenRelayZeroState, create_aes_gcm_private_codec

# Provision this as a 64-hex-character secret in your own secret manager.
key_bytes = bytes.fromhex(os.environ["SEENRELAY_L1_KEY_HEX"])

edge = SeenRelayZeroState(
    private_store=fleet_store,  # sync/async get(key) + set(key, sealed_value)
    private_codec=create_aes_gcm_private_codec(key_bytes),
    private_max_age_ms=30_000,
)

The built-in codec requires exactly 32 key bytes and uses AES-256-GCM. Store/codec/decrypt failures fail open to normal validation. A private L1 hit is never relabeled as an independent OBSERVE. The base seenrelay install remains dependency-free; only the built-in AES helper needs the optional crypto extra.

Coordinate fingerprints match the JavaScript Zero-State contract for interoperable JSON values. Python rejects integers that cannot be represented exactly by JavaScript numbers instead of silently changing the coordinate. The built-in encrypted payload formats intentionally do not claim mixed-language ciphertext interoperability. A mixed Python/JavaScript fleet that shares one private store must provide one caller-owned codec format understood by both languages.

Ambient MCP

Python can start in local-only shadow mode with no SeenRelay network call and no result suppression:

from seenrelay_ambient import ambient_mcp_client

client = ambient_mcp_client(raw_mcp_client, server_key="docs")
# await client.call_tool(...) normally
print(client.get_report())

For OpenAI Agents Python:

from seenrelay_ambient import ambient_openai_agents_mcp_server

server = ambient_openai_agents_mcp_server(raw_mcp_server)
# pass `server` to the Agent exactly as before

The report stores aggregate metrics plus SHA-256 fingerprints only. It identifies exact repetition worth reviewing; it does not claim savings. Active Ambient reuse is intentionally unavailable in the Python client; Zero-State must be configured explicitly around a caller-controlled read-only validation path.

Install

pip install seenrelay

Smallest integration: bind once, one line per revalidation

from seenrelay import SeenRelayClient
from seenrelay_easy import protect_validation

relay = SeenRelayClient()

validate_price = protect_validation(
    relay,
    fact=fact,
    validate=lambda ctx: expensive_validation(ctx.conditional_headers),
)

value = validate_price(known_value)

That is strict shadow mode by default: SeenRelay CHECK runs, your original validation still runs, and the independently obtained result is OBSERVEd best-effort. Nothing is skipped merely because SeenRelay is installed.

Only after measurement and policy approval should you add an explicit reuse policy:

from seenrelay import reuse_known_on_same_observed

validate_price = protect_validation(
    relay,
    fact=fact,
    validate=lambda ctx: expensive_validation(ctx.conditional_headers),
    reuse=reuse_known_on_same_observed,
)

Direct client form

value = relay.guard(
    fact=fact,
    known_value=known_value,
    validate=lambda ctx: expensive_validation(ctx.conditional_headers),
)

Without an explicit reuse policy, validation is never skipped.

Prove value before enabling reuse

from seenrelay import SeenRelayClient
from seenrelay_shadow import SeenRelayShadowProof

proof = SeenRelayShadowProof(SeenRelayClient())

value = proof.guard(
    fact=fact,
    known_value=known_value,
    validate=lambda ctx: expensive_validation(ctx.conditional_headers),
)

print(proof.report(
    avoided_validation_cost=0.01,
))

Python Shadow Proof keeps the original validation. It measures CHECK status distribution, validation time and SeenRelay request latency locally. Potential savings count only SAME_OBSERVED calls and subtract caller-supplied request costs. Savings from conditional ETag / Last-Modified requests are deliberately excluded unless measured separately by the application.

Use SeenRelay around repeated validation that is materially more expensive than the preflight: paid search, scraping/proxy work, browser or extraction calls, rate-limited APIs, model-assisted parsing, or multi-step validation. It is generally a poor fit for a cheap one-off GET.

Protocol boundary

The Python client does not add a SeenRelay operation. The hosted service still exposes only CHECK and OBSERVE and does not browse, search or verify arbitrary facts on demand.

License

The client package is MIT licensed. The hosted SeenRelay service implementation remains governed by the repository root license.

Ambient framework integrations

All integrations below are optional. SeenRelay imports the framework only when the corresponding adapter is requested. Ambient measurement is local-only, preserves the authoritative call, and never enables reuse automatically.

from seenrelay_ambient import ambient_langchain_mcp_client
client = ambient_langchain_mcp_client(client)
tools = await client.get_tools()
print(client.seenrelay_ambient["get_report"]())

from seenrelay_ambient import ambient_pydantic_ai_toolset
toolset = ambient_pydantic_ai_toolset(toolset)

Coding agents and integration tooling can inspect the installed package without network discovery:

from seenrelay_ambient import ambient_integration_catalog
print(ambient_integration_catalog())

The catalog is local metadata only. It adds no telemetry, hosted operation, or reuse authorization.