Identity Initial Overview and Big Picture#9
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Added an overview document for the Identity for Agents workstream, detailing unique identity challenges and the evolving nature of identity standards in agent systems. Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
Added a comprehensive overview of identity, authentication, and authorization standards relevant to ACS, including existing and emerging standards, their gaps, and the role of ACS in addressing these gaps. Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
ashayraut
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ashayraut
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This document correctly identifies the composition boundary between token-issuance standards (AIMS, OIDC, WIMSE) and runtime enforcement (ACS). The framing is sound. However, the OAuth assumptions table has structural gaps that weaken the argument:
-> Token lifetime is treated as a refresh-token problem. It's not. The core broken assumption is that access tokens can live for 60 minutes. For agents, any token outliving the current reasoning step is ambient authority waiting to be exploited. This needs its own row.
-> Permission accumulation is invisible. OAuth assumes stateless, non-accumulating permissions per request. Agents with persistent memory carry forward effective authority across sessions — the token scope is fixed but the agent's de facto capability grows. The document doesn't name this.
-> What about position on impersonation vs. delegation? The document describes delegation chains but avoids the hard architectural question: should agents ever impersonate users, or must they always act on-behalf-of with attenuated scope? Taking a position here (or explicitly marking it as an open question) would strengthen the spec.
-> Thoughts on Revocation - its is incomplete without memory invalidation. Revoking a token stops future API calls. It doesn't undo what the agent already learned or cached from that token's access. Maybe the document should acknowledge that revocation in an agentic context requires purging derived context, not just killing the credential.
Cross-resource scope union is unaddressed. An agent holding tokens for Calendar + Email + Drive has an effective permission set no single OAuth grant authorized. The dangerous triad (sensitive data access + untrusted input exposure + external communication) emerges from this union, and per-resource aud restrictions don't prevent it.
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Also - consider changing the doc location to: |
rocklambros
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rocklambros
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The direction is right: trust standards establish identity but don't enforce what an authenticated agent does at runtime, and that's ACS's lane. Most citations check out too (RFC 8693/6750/9396, the OAuth-WG splicing post, NIST, Unit 42). Requesting changes on a few specific items, then this is good to go.
Before merge:
- standards.md treats WIMSE as the normative agent identifier ("WIMSE identifier required; SPIFFE conformant"), but the normative
docs/concepts/identity.mdsays ACS mandates no auth mechanism and keeps schemes like SPIFFE/OIDC off the wire, so aposix_uidoroauth_subjectdeployment stays conformant. The two pages answer "does ACS require WIMSE" in opposite ways. A mandate should land in identity.md with WG sign-off rather than here. - The AIMS "TODO Security" quote has moved on. draft-klrc-aiagent-auth-02 (2026-06-01) has Security Considerations at §13 with real prose, and §14 is now "Privacy Considerations," so the link no longer backs the quote. "AIMS scopes runtime enforcement out of its model (§13)" keeps the point.
- The "ACS §3.1 / 15 min / 5 min / 60 s" ceilings don't resolve against the spec: §3 is Wire Format, and those values aren't in docs/ or specification/. Worth marking proposed or open-work-item until there's a clause to cite.
- "the same user, returning later" isn't in RFC 6749 §1.5 (the text there is functional), so dropping the quote marks keeps it as your paraphrase. Quick check on the arXiv 2602.19555 title pairing too.
- Both files sit at repo-root identity/, outside
docs_dir, so mkdocs won't build them and they're missing from nav, while docs/concepts/identity.md already covers this space. If that's deliberate staging, note it in the file; otherwise move under docs/ and cross-link.
Smaller, not blocking: no-cache vs the fail-open §6.4 default, "detects deviation" reading as detection when intent immutability really confines scope, the mermaid fence isn't configured, "seven concepts" is eight once you count Skill. Happy to pair on the identity.md reconciliation.
Each item has a falsifying test in adapters/_common/tests/test_edge_cases.py (17 tests total). Items not requiring code changes still have tests that codify the safe behavior so a future regression would be caught. ## Items 1-12 Agent-Control-Standard#1 rfc8785 JCS consistency — test confirms fallback matches the rfc8785 package byte-for-byte on every ACS envelope shape we ship. No code change needed; a mixed-install signature mismatch would surface as test failure. Agent-Control-Standard#2 Guardian regex DoS, server-side: _matches_destructive_bash now returns "too_large" for inputs > DESTRUCTIVE_SCAN_MAX_LEN (8 KiB). The Guardian denies with reason_codes=["input_too_large"] — fail-safe direction. Previously, _common had the cap but the Guardian iterated patterns directly, leaving the server unprotected. Agent-Control-Standard#3 HA Guardian replay window: persist() now takes an exclusive flock on a .lock sidecar, re-reads on-disk state, merges (union of seen_request_ids / seen_nonces with earliest-timestamp wins), and atomically writes. check_replay re-reads the state on every call so Guardian A's writes are visible to Guardian B within one request. Cross-instance replay window closed under shared ACS_GUARDIAN_STATE_DIR. Agent-Control-Standard#4 Unbounded seen_request_ids: switched to dict {rid: timestamp}. New evict_old_request_ids() drops entries older than 2 × skew window (replay impossible past skew anyway). check_replay calls eviction opportunistically every 100 inserts. Memory bound is now O(skew_window / inter-request-time), not unbounded. Backwards- compat for list-format state files preserved. Agent-Control-Standard#5 Handshake cache TTL: do_handshake skips cache files older than ACS_HANDSHAKE_CACHE_TTL_SECONDS (default 3600s). Operator config changes propagate within the TTL. Agent-Control-Standard#6 NAT id(context) collision: WeakKeyDictionary fallback for contexts that reject attribute assignment. Last-resort path (object isn't weak-referenceable either) returns a fresh uuid4 per call and emits an audit event — pre→post correlation is lost in that path, but no silent collision. Agent-Control-Standard#7 Unicode / NULL / surrogate round-trip: emoji, NULL bytes, multi- plane unicode all sign+verify cleanly. JCS handles them via UTF-8 encoding; no code change needed. Agent-Control-Standard#8 ISO 8601 parse resilience: parse_iso8601 already accepts Z suffix, timezone offsets, millisecond + microsecond precision. Test codifies the accepted shapes + asserts garbage is rejected. Agent-Control-Standard#9 ACS_GUARDIAN_HOST_ALLOWLIST: optional env-var allowlist that restricts validate_guardian_url to specific hostnames in addition to the http/https scheme check. Defense in depth against env-var attacks that smuggle a valid http:// URL to internal services. Agent-Control-Standard#10 Cursor session-state file collision: _session_state_path now accepts an optional workspace parameter folded into the hash key. Cursor adapter passes the workspace_path / cwd so two Cursor windows with the same non-UUID conversation_id can't share state. Agent-Control-Standard#11 Guardian envelope schema validation: if jsonschema + ACS_SPEC_DIR are available, every incoming envelope is validated against request-envelope.json before policy evaluation. Malformed envelopes rejected with -32600 Invalid Request. system/ping and handshake/hello exempt because their payload shapes differ. Agent-Control-Standard#12 State-file hash length: bumped _session_state_path and _handshake_cache_path hashes from sha256[:16] (64-bit) to full sha256 (256-bit). Eliminates birthday collisions over deployment lifetime. ## Test counts after this commit (all green, 1 intentional manual skip) _common: 33 (16 security + 17 edge-cases) claude-code: 32 cursor: 50 example-guardian: 20 nat: 24 Total: 159 tests. ## Side-effects of the fixes - Round-trip test fixtures updated to use real UUID session_ids (claude-code/test_adapter.py). Old "test-cc-session" fails the new Guardian-side envelope-schema check, which is correct — non-UUID session_ids never reached the Guardian from real Claude Code. - Cursor adapter wires workspace through to load/save/record session state for Agent-Control-Standard#10 (new _workspace helper). - example_guardian.py imports DESTRUCTIVE_SCAN_MAX_LEN from acs_common to keep the cap in one place. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Updated various sections to clarify the scope of AIMS and ACS, including token lifetimes, identifier models, and runtime enforcement. Added details on agent behavior and security considerations. Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
Updated the overview document to reflect the feedback in the comments Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
Updated the identity standards document to focus on agents, outlining unique identity challenges and how ACS addresses them. Added sections on existing and emerging standards, and clarified the relationship between ACS and AIMS. Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
Signed-off-by: Eva <130791729+evabenn@users.noreply.github.com>
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@rocklambros @bar-capsule Moved both files to |
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Adds the Identity for Agents workstream overview as a working document.
This PR adds
overview.md— the 5 unique runtime identity challenges that distinguish agent systems from human/workload identity (chain integrity, over-privilege, token theft resistance, last-mile enforcement, proof of intent), with each mapped to where existing standards fall short.Next steps (for working group discussion)