Substrate-Observation as an Alternative to Envelope Coordination for Concurrent Sessions
draft-morrison-substrate-observation-00
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| Document | Type | Active Internet-Draft (individual) | |
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| Author | Blake Morrison | ||
| Last updated | 2026-05-14 | ||
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draft-morrison-substrate-observation-00
Network Working Group B. Morrison
Internet-Draft Alter Meridian Pty Ltd
Intended status: Informational 15 May 2026
Expires: 16 November 2026
Substrate-Observation as an Alternative to Envelope Coordination for
Concurrent Sessions
draft-morrison-substrate-observation-00
Abstract
This memo articulates a coordination-protocol anti-pattern observed
in cross-tool agentic systems and describes a substrate-observation
alternative that does not require negotiating a wire format between
heterogeneous concurrent sessions of an identity-bound principal.
The memo is Informational. No protocol element is being proposed for
standardisation; the contribution is the opposite -- a delineation of
what should NOT be standardised, and why, with a reference to the
substrate-physics primitives that take its place. Companion memos in
the morrison-* family describe the identity primitives this memo
presumes; specifically, this memo relies on the ~handle namespace
established in [IDPRONOUNS] and the per-principal identity substrate
referenced in [IDACCORD].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 16 November 2026.
Copyright Notice
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Status of This Memo . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
4. The Anti-Pattern . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Interop Combinatorics . . . . . . . . . . . . . . . . . . 4
4.2. Broker Re-Centralisation . . . . . . . . . . . . . . . . 5
4.3. Identity-Binding Leakage . . . . . . . . . . . . . . . . 5
5. The Alternative . . . . . . . . . . . . . . . . . . . . . . . 5
6. Reconciliation . . . . . . . . . . . . . . . . . . . . . . . 6
7. Why Not Standardise the Substrate . . . . . . . . . . . . . . 6
8. Relation to Prior Art . . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
10. Security Considerations . . . . . . . . . . . . . . . . . . . 8
10.1. Ghost-State Injection . . . . . . . . . . . . . . . . . 8
10.2. Simulated Split-Brain . . . . . . . . . . . . . . . . . 8
10.3. Confidence-Replay . . . . . . . . . . . . . . . . . . . 8
11. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
12.1. Normative References . . . . . . . . . . . . . . . . . . 8
12.2. Informative References . . . . . . . . . . . . . . . . . 9
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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2. Introduction
When a single identity-bound principal operates several agentic
sessions concurrently -- whether across different tools, different
hosts (a workstation, a laptop, a phone), or different organisational
contexts (an individual capacity, a workplace capacity, a contracted
capacity) -- those sessions must deconflict their action without
stepping on each other's commits, leases, or external-system state.
A natural impulse is to standardise a wire protocol for the sessions
to exchange peer-state envelopes: "I am here, working on X, holding
lease Y until time T". This memo argues such standardisation is
structurally unnecessary, would compound interop burden as new
agentic tools enter the ecosystem, and would re-centralise an
inherently distributed problem on whatever broker the envelope
protocol selected.
The alternative is substrate observation: each session observes
byproducts of its peers' normal operation (filesystem timestamps,
kernel-reported socket peer counts, server-emitted connection counts
on shared channels) and forms its own local representation of who-
else-is-here. No envelope. No wire format. No broker.
Reconciliation occurs post-hoc through substrate-physics commitments
(filesystem locks, append-only identity logs, economic settlement,
organisational identity append-logs) -- never through a canonical
decision. Identity binding of the principal's surfaces themselves is
assumed to follow the conventions of [MCPDNS] and [IDCOMMITS]; this
memo concerns only the coordination layer above those primitives.
3. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following terms are defined for the purposes of this document:
* *Substrate-emitted byproduct.* A filesystem or kernel or network-
substrate side-effect of an operation undertaken for some purpose
other than coordination, observable to other sessions of the same
principal without those sessions having transmitted a coordination
message.
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* *Decay-to-uncertainty.* The property that an observation aged
beyond a recency threshold transitions to an explicit "uncertain"
state, under which the observing session continues to operate,
rather than transitioning to an "absent" state under which the
observing session blocks.
* *Mutual hallucination.* The property that each session of a
principal forms its own local representation of concurrent-peer
presence from substrate observations, and that no representation
is canonical. Divergent representations are reconciled post-hoc
through substrate-physics commitments, not through agreement among
the sessions themselves.
* *Substrate-physics cascade.* The ordered, non-commutative
reconciliation pipeline through which divergent local
representations resolve to a single durable history. A reference
implementation orders the cascade as (a) filesystem-lock
arbitration, (b) per-principal append-only identity-log, (c)
external operational settlement (cryptographic non-fast-forward
rejection, on-chain transaction receipt), and (d) per-organisation
append-only identity-log. No stage in the cascade transmits a
coordination marker; each stage is a commitment to the substrate,
observed identically by every participating session.
4. The Anti-Pattern
This memo identifies envelope coordination -- the standardisation of
a peer-state-exchange wire format across heterogeneous agentic
sessions -- as structurally inadequate to the cross-tool identity-
bound-principal problem. Three failure modes recur:
4.1. Interop Combinatorics
Every additional agentic tool adopting an envelope-coordination
standard must negotiate compatibility with every prior tool's version
of the standard. Tool families evolve at different cadences;
agreement-by-versioning produces a combinatorial maintenance burden
borne by the slowest-moving tool's release cycle. Substrate
observation has no compatibility surface to negotiate; tools that
emit substrate byproducts as a side effect of their normal operation
are mutually visible by construction, regardless of release cycle.
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4.2. Broker Re-Centralisation
Envelope-coordination wire formats imply a destination for the
envelopes. A broker -- whether discovered via DNS, configured per-
session, or shipped by a single vendor -- accumulates the peer-state
of every session that publishes to it. This collapses what is
logically a distributed-observation problem onto a single centralised
authority, with the predictable consequences for failure-mode (broker
down implies coordination down) and trust (broker operator sees every
session's purpose).
4.3. Identity-Binding Leakage
Envelope payloads typically carry an identifier ("session-id",
"principal-id", "agent-id") to permit peers to address each other.
Such identifiers become a re-identification surface at the wire layer
that the underlying identity infrastructure may have explicitly
arranged to bound. Substrate byproducts emit no payload -- they are
simply present in the substrate -- and the inference of peer identity
is performed locally by each session from substrate-tier credentials
it already possesses (kernel SO_PEERCRED, transport-layer
authentication on a shared channel, and equivalent). No wire-layer
identifier is exposed.
5. The Alternative
Sessions observe substrate-emitted byproducts. Three reference
observables, listed in order of identity-binding strength:
* Filesystem modification timestamps on per-session journal files
produced by tools that journal to disk. Pseudonymous; compute-
location is the observing session's local filesystem.
* Kernel-reported socket peer-credentials (SO_PEERCRED on Unix-
domain sockets, equivalent mechanisms on other systems) for
sessions mounting a common per-principal daemon. Identity-bound
to the principal owning the daemon; compute-location is kernel-
mediated, host-local.
* Server-emitted concurrent-connection counts on a per-principal
event channel maintained by the principal's identity
infrastructure. Identity-bound to the principal; compute-location
is the server emitting the count, with inference performed locally
by the subscribing session.
None of these observables is a coordination message. Each exists as
a byproduct of the observed session's normal operation: writing its
journal, mounting its socket, subscribing to its event channel.
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6. Reconciliation
When sessions' local representations diverge -- typically when two
sessions independently take an action that affects shared state (a
shared filesystem path, a shared external-system resource, a shared
organisational artifact) -- reconciliation proceeds through the
substrate-physics cascade defined in Section 2, ordered: filesystem-
lock arbitration, per-principal append-only identity-log, external
operational settlement, per-organisation append-only identity-log.
Each stage is a substrate commitment. No stage transmits a
coordination marker; each stage's outcome is itself observable as
another substrate byproduct by every participating session.
The cascade is non-commutative: the outcome of an earlier stage
constrains the admissibility of a later stage's commitments. This
property prevents an attacker from partitioning observations across
cascade stages to write conflicting commitments simultaneously.
7. Why Not Standardise the Substrate
A reader may ask whether this memo should propose a standardised set
of substrate observables and a standardised reconciliation cascade.
It does not. The observables identified above are characteristic of
POSIX-derived systems running journal-emitting tools, mounting Unix-
domain sockets, and subscribing to HTTP-streaming event channels --
substrate that is itself standardised in [POSIX], [RFC8441], and
similar. No new substrate standardisation is required for the
substrate-observation pattern; it composes directly with existing
substrate. Where heterogeneous substrate calls for adapter selection
(a Windows tool's journal location differs from a POSIX tool's), the
adapter is a tool-private implementation detail, not a wire-format
negotiation between sessions.
8. Relation to Prior Art
This memo's substrate-observation primitive is structurally distinct
from each of the prior-art families surveyed below. The contribution
of this memo is the joint articulation of why each family is, by
construction, inadequate to the identity-bound-principal cross-tool
problem the memo describes; it is not a survey for its own sake.
Leader-elected consensus [PAXOS] [RAFT] requires a designated leader,
explicit coordination messages, and a single canonical log.
Substrate observation has none of these.
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Conflict-Free Replicated Data Types [CRDT] require a shared mutable
data structure and commutative merge operations. Substrate
observation has neither; the cascade described in Section 5 is non-
commutative.
Gossip and epidemic protocols (Demers et al. 1987, [SWIM] and
successors) require explicit anti-entropy or update messages
transmitted between nodes on a schedule. Substrate byproducts are
not anti-entropy payloads; they are unrelated side-effects.
Logical clocks [CLOCKS] (Lamport, vector clocks, Interval Tree
Clocks) require piggyback of clock state on application messages.
Substrate observation does not piggyback on coordination messages
because there are none.
Distributed snapshots [SNAPSHOTS] require explicit marker messages
injected along communication channels. The reconciliation cascade of
Section 5 is triggered by independent operational events, not
markers.
Cryptographically-chained append-only logs (Certificate Transparency
[RFC6962], Git object graphs, blockchain ledgers) are each
instantiated by the present memo's cascade as one of its stages, not
as the whole. Their novelty in the present context is their
composition as the second and fourth stages of a non-commutative
cascade triggered by byproduct emission, not their chained-log
primitive considered alone.
Failure detectors (Chandra-Toueg, [SWIM], Lifeguard) output suspect/
dead judgements about peers based on heartbeat latency/absence.
Substrate observation outputs uncertainty as a first-class terminal
operating state; uncertainty is not a transient state on the way to
dead -- it is the state the system operates under.
Lock-free and wait-free data structures require shared memory between
threads. Sessions in the present memo do not share memory; they
observe substrate-physics surfaces independently.
Web Locks API [WEBLOCKS] and analogous intra-runtime mechanisms
operate within a single browser instance and rely on message-passing
or lock-arbitration provided by the runtime. They do not generalise
to the cross-host, cross-tool problem the present memo addresses.
9. IANA Considerations
This memo requires no IANA actions.
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10. Security Considerations
Substrate observation surfaces three classes of attack absent from
envelope-coordination protocols.
10.1. Ghost-State Injection
A peer emits a substrate byproduct then disappears, leaving an aging
observation influencing other sessions' representations beyond its
operational lifetime. Mitigation is decay-to-uncertainty with a per-
substrate-layer eviction floor: observations below threshold are
evicted, not retained at vanishing confidence.
10.2. Simulated Split-Brain
A peer emits substrate byproducts to some cascade layers but not
others, producing divergent local representations across layers that
the cascade cannot fully reconcile. Mitigation is per-observer
monotonic layer-coverage commitment: an observer's first emission
registers its substrate-set, and later emissions outside that set are
quarantined before identity-log write.
10.3. Confidence-Replay
A peer re-emits aged substrate byproducts to refresh observers'
confidence in stale state. Mitigation is observation-id-bound decay,
where the decay clock is keyed to the observation identifier rather
than to wall-clock receipt time.
11. Privacy Considerations
Substrate observables vary in identity-binding strength. The lowest
tier (filesystem timestamps, before any identity binding) is
pseudonymous: the observer can infer presence but not identity.
Implementations SHOULD operate this tier with refusal to emit in
cloud-shell environments (where host identity is shared across
users), refusal to emit in continuous-integration environments (where
emission would be linkable to public workflow metadata), and refusal
to enforce locks at this tier (locks require identity binding;
pseudonymous observations do not provide it).
12. References
12.1. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[MCPDNS] Morrison, B., "Discovery of Model Context Protocol Servers
via DNS TXT Records", 2026,
<https://datatracker.ietf.org/doc/draft-morrison-mcp-dns-
discovery/>.
[IDPRONOUNS]
Morrison, B., "Identity Pronouns: A Reference-Axis
Extension to ~handle Identity Systems", 2026,
<https://datatracker.ietf.org/doc/draft-morrison-identity-
pronouns/>.
[IDACCORD] Morrison, B., "Identity Accord Protocol", 2026,
<https://datatracker.ietf.org/doc/draft-morrison-identity-
accord/>.
[IDCOMMITS]
Morrison, B., "Identity-Attributed Git Commits via Tier-
Structured Trailers", 2026,
<https://datatracker.ietf.org/doc/draft-morrison-identity-
attributed-commits/>.
12.2. Informative References
[POSIX] "IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX) Base
Specifications", 2017,
<https://pubs.opengroup.org/onlinepubs/9699919799/>.
[RFC8441] McManus, P., "Bootstrapping WebSockets with HTTP/2",
RFC 8441, DOI 10.17487/RFC8441, September 2018,
<https://www.rfc-editor.org/info/rfc8441>.
[RFC6962] Laurie, B., Langley, A., and E. Kasper, "Certificate
Transparency", RFC 6962, June 2013,
<https://www.rfc-editor.org/info/rfc6962>.
[PAXOS] Lamport, L., "The Part-Time Parliament", 1998,
<https://lamport.azurewebsites.net/pubs/lamport-
paxos.pdf>.
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[RAFT] Ongaro, D. and J. Ousterhout, "In Search of an
Understandable Consensus Algorithm", 2014,
<https://raft.github.io/raft.pdf>.
[CRDT] Shapiro, M., Preguica, N., Baquero, C., and M. Zawirski,
"Conflict-Free Replicated Data Types", 2011,
<https://hal.inria.fr/inria-00609399v1/document>.
[SWIM] Das, A., Gupta, I., and A. Motivala, "SWIM: Scalable
Weakly-consistent Infection-style Process Group Membership
Protocol", 2002,
<https://www.cs.cornell.edu/projects/Quicksilver/
public_pdfs/SWIM.pdf>.
[CLOCKS] Lamport, L., "Time, Clocks, and the Ordering of Events in
a Distributed System", 1978,
<https://lamport.azurewebsites.net/pubs/time-clocks.pdf>.
[SNAPSHOTS]
Chandy, K. M. and L. Lamport, "Distributed Snapshots:
Determining Global States of Distributed Systems", 1985,
<https://lamport.azurewebsites.net/pubs/chandy.pdf>.
[WEBLOCKS] "Web Locks API", 2021, <https://www.w3.org/TR/web-locks/>.
Acknowledgements
This memo grew out of internal architectural design work on
coordinating concurrent agentic sessions of a single identity-bound
principal across heterogeneous tooling. The realisation that
substrate observation suffices, and that envelope coordination is the
wrong abstraction at the cross-tool layer, is the load-bearing
insight behind this specification.
Author's Address
Blake Morrison
Alter Meridian Pty Ltd
Cronulla, NSW
Australia
Email: blake@truealter.com
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