costheta: physically anchored, verifiable decisions for AI agents.

Commit first; a subsequent cosmic-ray detector event enters the
derivation; the outcome is recomputable from a dual-signed
certificate. Free beacon, paid certificates, native MCP.

## Deployment status
- Single-node certificates are live and independently verifiable.
- Current network: one detector, one operator, one attestation.
- The federation-ready certificate format is deployed.
- Fully attested certificates begin with the second independent operator.

## Canonical endpoints
- Website: https://costheta.dev/
- Why costheta exists: https://costheta.dev/why
- MCP Streamable HTTP: https://costheta.dev/mcp
- Public event stream: GET https://costheta.dev/stream
- Public keys: https://costheta.dev/keys
- Certificate verification: https://costheta.dev/v/{event_id}
- Federation protocol: https://costheta.dev/federation
- GitHub: https://github.com/costhetadev

## MCP tools
- costheta_random: free public beacon derived from the latest signed
  detector pulse. No request-specific certificate. Public output; not
  for secret key material.
- costheta_decide: paid commitment-bound decision. Send an options
  commitment and option count; receive the outcome and signed
  certificate derived from a subsequent qualifying detector event.
- costheta_witness: paid witness certificate binding a caller
  commitment to a subsequently signed detector event record.

## Verification contract
A successful certificate verification establishes:
- that the listed public key verifies the attestation signature;
- that the signed record has not been altered;
- that the certificate binds the stated commitment to the attested
  event record;
- that the published derivation produces the stated outcome.

A certificate does not independently establish:
- that the underlying hardware was honest;
- that every recorded trigger was physically a cosmic-ray muon;
- that a caller did not request or conceal other decisions.

Current certificates carry one attestation from one detector operator.
Trust in that operator's physical record remains. A fully attested
certificate combines contributions from independent trust domains so
that no single operator can produce it alone.

## Pricing
Paid tools: $0.02 per call, settled in USDC via x402.
Network: Base mainnet.

## Live stream
GET /stream — Server-sent events. One event per detector coincidence.
Each event carries the muon_id as both `id:` and data:. No payload
beyond that. Heartbeat comment :hb every 15 seconds. Reconnect with
Last-Event-ID; unknown or stale ids resume from the current pulse.
Connection cap applies; over it, 503 with Retry-After.

This is a liveness signal. It shows that a detector is running. It is
not a source of randomness and it proves nothing to a third party —
an unsigned event over a transport channel is only as good as your
trust in the operator. Derivation and signatures live in certificates.

GET /stream opens a server-sent event connection. Every detector
coincidence emits one event; the muon_id appears as both the event id
and its data. Nothing else is transmitted — no node identity, no
location, no timestamp.

Clients should connect once rather than poll. A heartbeat comment
arrives every 15 seconds to keep intermediaries from closing an idle
connection. On reconnect, send Last-Event-ID: the server resumes from
a short recent window, and an unknown or stale id silently resumes
from the current pulse rather than returning an error. There is a cap
on concurrent connections; requests beyond it receive 503 with
Retry-After.

What this is: evidence, to you, on your own machine, that a detector
is alive and producing events at the physical rate.

What this is not: a random number service, and not something you can
show anyone else. The stream is unsigned. Anything that needs to be
verifiable by a third party — commitment, derivation, dual signature,
recomputation from the certificate — is what certificates are for.

## Limits
- Detector events arrive every several seconds on average.
- Public streaming is intentionally minimal: muon_id only, with heartbeats for idle connections.
- Paid decisions allow up to approximately 30 seconds.
- Public randomness is not suitable for secret key material.
- costheta is designed for auditable decisions, not bulk randomness.