Changelog

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All notable changes to this project are documented here. The format is based on Keep a Changelog and this project adheres to Semantic Versioning.

[1.0.0] - 2026-07-04

First stable release; the public API is now under semantic versioning. No functional change from 0.11.0. Requires attesto ~> 1.0.

[0.11.0] - 2026-06-23

Added

  • Clustered + persistent Anubis MCP session infrastructure (optional, compile-guarded — an RS-only consumer pays nothing):
    • AttestoMCP.Anubis.SessionStore.Ecto — a Postgres-backed Anubis.Server.Session.Store. Anubis ships only a Redis adapter; this persists the session map (keyed by Mcp-Session-Id) so a client reconnects after a deploy/node-replacement with its initialized state restored instead of re-initializing. Stateless (start_link/1 is :ignore, rides the host repo), with lazy + scheduled (cleanup_expired/1) TTL reaping. Backed by the AttestoMCP.Anubis.Session schema; mix attesto_mcp.gen.session_migration creates the attesto_mcp_sessions table. Compile-guarded on Ecto.Schema.
    • AttestoMCP.Anubis.JSONSafe.sanitize/1 — strips non-JSON-encodable values (bare structs, pids, refs, tuples, functions) from session state before the jsonb insert, since Anubis folds the whole request assigns into the persisted frame; without it the driver raises mid-initialize and kills the session process.
    • AttestoMCP.Anubis.Registry.Horde — a cluster-wide Anubis.Server.Registry that keeps the client-supplied session_id as CRDT/ETS data (a :via tuple), closing the atom-table-exhaustion DoS in the bundled :pg adapter (which derives a never-GC'd atom per session id), and routes a request landing on any node to the node holding the session. Compile-guarded on Horde.Registry.
    • mix attesto_mcp.install.sessions — an Igniter installer that writes the config :anubis_mcp, :session_store block (and, with --registry, adds the horde dependency), and prints next-step notices for the migration and the supervision-tree registry wiring.

[0.10.0] - 2026-06-22

Added

  • RFC 9470 Step-Up Authentication. AttestoMCP.Plug.ProtectResource / Plug.Authenticate accept a per-route :step_up requirement ([acr_values: [...], max_age: ...]); after the token is verified its acr / auth_time claims must satisfy it or the request is refused 401 insufficient_user_authentication naming what the client must re-request.

  • attesto_mcp_protected_resource_metadata/2 accepts root: true | false to control the unsuffixed RFC 9728 root compatibility document explicitly.

Changed

  • The root /.well-known/oauth-protected-resource compatibility document is now auto-mounted only for a single-resource router. Once more than one resource is declared its resource is ambiguous, so the host must choose with root: true (nominate the resource) or root: false (serve no root); a second resource that leaves the root implicit is a compile error. Previously the root silently resolved to whichever resource was declared first, which could publish a sensitive resource's metadata at a guessable path by accident.

[0.9.0] - 2026-06-22

Added

  • RFC 8707 / RFC 9728 per-resource audience confinement. AttestoMCP.Plug.ProtectResource / Plug.Authenticate gain a :resource_audience option: with :resource (or a string / (conn -> uri) / {m, f} value) the access token's aud is validated against THIS resource's identifier rather than the host's global config.audience, so a token minted for a sibling resource is rejected (audience confinement, RFC 8707 §1).
  • AttestoMCP.Metadata.resource_identifier/3 — the single canonical origin-plus-path identifier shared by the advertised metadata resource and the validated audience, so metadata.resource == requested resource == minted aud == validated aud holds by construction.

Changed

  • Requires attesto ~> 0.10. :resource_audience: :resource raises (fails closed) when no resource path is configured to derive the identifier from.

[0.8.0] - 2026-06-21

Changed

  • MCP protected-resource authentication defaults to header-only bearer credentials. AttestoMCP.Plug.Authenticate and ProtectResource pass bearer_methods: [:header] to attesto core unless the host opts in with bearer_methods: [:header, :body]. This matches the MCP protected-resource metadata default of bearer_methods_supported: ["header"]. Requires attesto ~> 0.9.

[0.7.0] - 2026-06-21

Added

  • AttestoMCP.Anubis.put_auth/1 — an optional bridge that projects the verified :attesto_context into an Anubis MCP server's frame.context.auth, so Anubis's framework-level authorization (the tools/list visibility filter, per-tool scope gates) sees the resource-server identity. anubis_mcp is an optional dependency and the module is compile-guarded on Anubis.Server.Frame, so a resource server that does not use Anubis never compiles it or pulls it in. The projection is purely mechanical — no scope-superset, role, or visibility policy, which stay in the host app.
  • AttestoMCP.Plug.Authenticate now assigns :attesto_context — a single protocol-shaped context map (%{subject, client_id, scope, claims, cnf, principal}), identical to the one AttestoPhoenix.Plug.Authenticate assigns, under the new :context_key option (default :attesto_context). This is the canonical cross-plug auth context the Anubis bridge reads, so the bridge works whether a request was authenticated by the MCP plug or the Phoenix plug.

Changed

  • MCP scope-rejection rendering now delegates fully to attesto core. AttestoMCP.Plug.RequireScopes renders its 403 insufficient_scope through Attesto.Plug.OAuthError.insufficient_scope/4, which now honors the :send_error / :www_authenticate / :no_store transport hooks. This removes the local 403 gap-filler and the AttestoMCP.Plug.Error shim (the on-the-wire challenge and body are unchanged). Requires attesto ~> 0.8.1.
  • The :no_store transport hook now threads through RequireScopes and ProtectResource, at parity with :send_error / :www_authenticate.

Fixed

[0.6.2] - 2026-06-14

Fixed

  • The mix attesto_mcp.install task no longer references Igniter.Mix.Task unconditionally, so attesto_mcp compiles in a consumer that does not depend on igniter. igniter is an optional dependency, but the install task did use Igniter.Mix.Task at the top level. In a consumer application that depends on attesto_mcp without also pulling in igniter (the common prod case), compiling attesto_mcp failed with module Igniter.Mix.Task is not loaded and could not be found. The task is now wrapped in a top-level if Code.ensure_loaded?(Igniter) guard: the Igniter-backed installer compiles only when igniter is present, and a use Mix.Task fallback that prints a "install igniter to use this task" message takes its place otherwise. Behavior is unchanged when igniter is available.

[0.6.1] - 2026-06-14

Fixed

  • AttestoMCP.Plug.ProtectResource can again be used as a compile-time router pipeline plug (plug_init_mode: :compile). 0.6.0 made init/1 bake the generated resource_metadata WWW-Authenticate closure into the RequireScopes transport. Under :compile mode (the Phoenix router / production default) a plug's init/1 result is embedded via Macro.escape, which rejects anonymous functions, so a router carrying the plug failed to compile. The generated challenge is now built at call time from an escape-safe spec (strings / {m, f} tuples), so init/1 returns no closures and the plug compiles in a :compile-mode pipeline. Behavior is unchanged: an insufficient-scope 403 still carries the resource_metadata pointer, and a host-supplied :www_authenticate still wins. (Callbacks the host passes to the plug must be remote captures or MFA tuples, not anonymous fn, to be embedded under :compile mode — the same constraint Plug imposes on every plug.)

[0.6.0] - 2026-06-14

Added

  • Origin pinning for protected-resource metadata behind a proxy. A host can now pin the advertised resource/challenge origin and authorization_servers instead of always deriving them from the live request connection, which behind a TLS-terminating proxy is both fragile (http/internal host) and an X-Forwarded-Host spoofing vector into the metadata document a client trusts to find its authorization server.
    • AttestoMCP.Metadata.resolve_origin/2 resolves the resource server origin: an explicit :base_url/:origin (a String.t() or (conn -> url)) wins over the request connection. It drives the resource identifier and the protected_resource_url/3 challenge URL.
    • AttestoMCP.Metadata.protected_resource/3 now defaults authorization_servers to the :config issuer (or an explicit :issuer string) when one is given, rather than the resource origin — the issuer is the authorization server the host already trusts. The resource identifier is not derived from the issuer (RFC 9728 keeps the two distinct).
    • The router macro attesto_mcp_protected_resource_metadata, AttestoMCP.MetadataController, AttestoMCP.Plug.Authenticate, and AttestoMCP.Plug.ProtectResource all accept and thread :base_url/:origin (and :issuer/:config), so the served metadata and the WWW-Authenticate resource_metadata challenge stay aligned when pinned. :base_url/:origin accept a string, a (conn -> url) callback, or a {module, fun} / {module, fun, args} tuple (so a dynamic origin works in a compiled router macro, where an anonymous fn cannot).
    • The generated resource_metadata challenge is now emitted consistently on every rejection the MCP plugs render - token failure, principal-callback rejection (a 401 from AttestoMCP.Plug.Authenticate), and insufficient-scope rejection (a 403 from AttestoMCP.Plug.RequireScopes via ProtectResource)
      • so a client is pointed at metadata on all of them, not just token failures.
    • New guides/proxy_origin.md documents the pinned-origin recipe so consumers do not reinvent a canonical-host guard plug.

Fixed

  • authorization_servers advertises the issuer verbatim: it is no longer trailing-slash-trimmed, since an issuer identifier is compared by exact string match (a trimmed path-based issuer would break discovery). The resource origin is still trimmed (it is joined with a path). A blank explicit :issuer is ignored rather than publishing [""] or overriding a configured issuer.
  • A blank, relative, or non-binary :base_url/:origin pin ("", "/", "/prefix", "mcp.example.com", …) is treated as "not configured" and falls back (:base_url → :origin → request origin) instead of producing relative or empty security metadata (no more resource: "/mcp" or authorization_servers: [""]). A pin must be an absolute scheme://… origin.
  • An explicit :resource / :authorization_servers now short-circuits the derivation, so a lower-precedence origin/issuer callback is never invoked (and cannot fail) for a value the host supplied outright. The resource origin is also resolved at most once per document and shared with the authorization_servers fallback, so a stateful origin callback cannot make the resource and authorization_servers disagree.

Changed

  • AttestoMCP.Metadata.protected_resource/3 now sets resource with put_new (was put), so an explicit :resource opt overrides the derived identifier — matching how :authorization_servers already behaved.
  • With no pinning options supplied, behavior is unchanged: both origins derive from the request connection.

[0.5.2] - 2026-05-31

Fixed

  • Correct the README installation snippet now that the package is published on Hex.

[0.5.1] - 2026-05-31

Changed

  • Reuse Attesto.Test.DPoP for MCP DPoP proof fixtures so downstream MCP tests stay aligned with Attesto's published DPoP helper API.

[0.5.0] - 2026-05-31

Added

  • AttestoMCP.Plug.ProtectResource: a single plug composing AttestoMCP.Plug.Authenticate then AttestoMCP.Plug.RequireScopes into a correctly ordered, halt-respecting pipeline, with the RFC 9728 resource_metadata WWW-Authenticate challenge auto-wired from the resource path.
  • AttestoMCP.Router with the attesto_mcp_protected_resource_metadata/2 Phoenix router macro, and AttestoMCP.MetadataController, serving per-resource /.well-known/oauth-protected-resource/<path> metadata plus a backwards-compatible root /.well-known/oauth-protected-resource route. The served resource identifier matches the ProtectResource challenge.
  • AttestoMCP.Test.DPoPAssertions: shipped ExUnit assertions for host apps proving a DPoP-bound token presented as a plain Bearer is rejected and is accepted with a valid DPoP proof.
  • guides/mcp_wiring.md: copy-pasteable end-to-end wiring guide.
  • phoenix as an optional dependency (only needed by AttestoMCP.Router and AttestoMCP.MetadataController).
  • Initial Plug/Phoenix authentication wrapper for protecting HTTP MCP endpoints with Attesto access-token verification, DPoP proof checks, and mTLS certificate-bound token checks.
  • MCP scope convention helpers.
  • OAuth protected-resource metadata builder and authorization-server metadata delegation.
  • Focused tests for Bearer, DPoP, mTLS, scope enforcement, principal mapping, custom error rendering, and public assign names.