Release 0.3.0 — AAuth Budgets resource side (first known implementation)

Author: abay94

CHANGELOG.md

@@ -1,5 +1,27 @@
 # Changelog
 
+## 0.3.0
+
+**AAuth Budgets** (draft-hardt-aauth-budgets, editor's copy) — the resource
+side, first known implementation (running in production on get4agent.com):
+
+- **Auth tokens** (`typ: aa-auth+jwt`): PS-issued budget carriers verified
+  against a configuration-pinned PS (`HttpsigConfig.trusted_ps`: issuer →
+  JWKS URL), `aud`-checked against `resource_url`, `cnf`-bound, ≤1h lifetime.
+- **`BudgetClaim` + `InMemoryMeter`**: atomic reserve → commit → release
+  pooled per the draft's `(iss, sub, aud)` aggregation key; conservative
+  crash-safety (an unresolved reservation counts as consumed); consumption
+  records **scoped to the presenting agent's `jkt`** so one agent never
+  learns about a sibling's spending.
+- **`BudgetMiddleware`** (FastAPI): `price_fn` hook, metering cycle,
+  refusals (401 + `AAuth-Requirement` with `reason=insufficient-budget` /
+  `budget-exhausted` and an optional resource token via
+  `resource_token_provider`), per-response `AAuth-Budget` header; error
+  responses release the reservation.
+- `build_aauth_budget_header` / `build_aauth_requirement` — RFC 9651
+  serialization (note: the field is a Dictionary, so members are
+  comma-separated; the draft's §11 example shows parameter separators).
+
 ## 0.2.0
 
 AAuth draft **-11** support (per the editor's copy, ahead of datatracker publication):

README.md

@@ -108,6 +108,36 @@ keyid-less shape is pinned in CI.
   [christian-posta/aauth-python-library](https://github.com/christian-posta/aauth-python-library) —
   this library is the thin relying-party verifier that handles both dialects.
 
+## Budgets: meter a spending envelope (draft-hardt-aauth-budgets)
+
+An agent can carry a PS-issued **auth token** (`typ: aa-auth+jwt`) with a
+`budget` claim — a spending envelope it uses offline, no per-call round trip
+to the control plane. The middleware does the whole resource-side checklist:
+verify the token against your pinned PS, atomically reserve → commit →
+release per request, answer with `AAuth-Budget`, and refuse exhausted
+envelopes with a `401` + `AAuth-Requirement` (optionally carrying your signed
+resource token with the agent's own consumption records — scoped to its key,
+so one agent never learns about a sibling's spending):
+
+```python
+from regent_httpsig import HttpsigConfig, HttpsigVerifier, InMemoryMeter
+from regent_httpsig.fastapi import BudgetMiddleware
+
+app.add_middleware(
+    BudgetMiddleware,
+    verifier=HttpsigVerifier(HttpsigConfig(
+        resource_url="https://api.example",
+        trusted_ps={"my-ps": "https://ps.example/jwks.json"},
+    )),
+    meter=InMemoryMeter(),
+    price_fn=lambda request: PRICES.get(request.url.path),  # max cost, minor units
+)
+```
+
+The only thing the library cannot do for you is pricing (`price_fn`) — that
+is your domain. First known implementation of the draft; running in
+production on [get4agent.com](https://get4agent.com).
+
 ## Security model (what a naive implementation gets wrong)
 
 The verifier fetches key directories from **attacker-nameable origins** — whoever signs a

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "regent-httpsig"
-version = "0.2.0"
+version = "0.3.0"
 description = "Verify and sign AI agent HTTP traffic in Python — RFC 9421 HTTP Message Signatures: Web Bot Auth (what OpenAI ships) and AAuth."
 readme = "README.md"
 license = "Apache-2.0"

src/regent_httpsig/__init__.py

@@ -22,7 +22,7 @@
 from regent_httpsig.sign import DIRECTORY_MEDIA_TYPE, EgressSigner, generate_seed
 from regent_httpsig.verify import WBA_TAG, HttpsigVerifier, VerifiedSignature
 
-__version__ = "0.2.0"
+__version__ = "0.3.0"
 
 __all__ = [
     "DIRECTORY_MEDIA_TYPE",