Status: accepted

Accepted — merged with intent to implement.

RFC 0112: Remove the retired agent host layer vocabulary from the standard

Accepted by the owner, 2026-10-21, as drafted (owner: "RFC 0112 (#474) accepted as drafted, including D2: keep the generic agent/<id> source with agent_id and agent_version."). Origin: owner decision D1 of 2026-10-12 ("Remove retired agent host entirely. Don't move it."), carried out as phase C of the public cleanup brief on the owner's instruction of 2026-10-21. The starter half, the agent runtime, providers and uwmd run, is removed separately without an RFC: RFC 0078 already classes retired agent host agents as starter products. This RFC covers what the Format, the Protocol and the schemas still say about retired agent host. It removes members that records and manifests carry, so it is normative.

Summary

The Format still describes one product's agent suite as if it were part of the standard. §1.3 maps retired agent host layers to sections. Frontmatter pipeline_state has one key per layer and refers to BANCROFT_LAYERS in the reference library. The section registry's "Written by" lines name layer agents (agent/L2-CRE-11). Part VI specifies the reference CLI, including uwmd run, and §6.8 sets MUST rules for "any retired agent host agent". Part VII specifies the reference renderer's outputs. Module manifests can declare agent_layers with a prompt_template. This RFC removes that vocabulary. Every rule that protects verification is kept in a form that applies to any producer. A record keeps saying who wrote each block, but no longer which layer of which product did.

Motivation

• The boundary test fails. A lender verifying a record from any producer should need only the standard (RFC 0078). The Format today names a product's layer registry, its CLI and its renderer, and §1.2 says that "proprietary tooling (retired agent host agents, uwmd CLI) is required to generate sections correctly."
• The product is gone. The owner removed the agent suite (D1). Vocabulary that points at a removed runtime is dead weight that every independent implementation has to read and ignore.
• Some of it is real. Several "Written by" lines carry prohibitions such as "an agent MUST NOT invent a tranche rate". Several §6.8 obligations (_meta first, revision increment) are producer rules. These are kept, so removing the vocabulary does not weaken them.

Proposed change

1. Format §1.2. Replace the "Toolchain-agnostic" sentence on proprietary tooling with: any producer that follows this specification can write sections, and no particular tool is required to write or read them.
2. Format §1.3 ("Relationship to the retired agent host Agent Suite") is deleted.
3. Frontmatter pipeline_state (Format §2.2) is removed with its layer keys and the L3 reservation (D4). Workflow position stays in status and deal_stage.
4. Section registry "Written by" lines (Part IV, 29 lines) are removed. Where a line carries a source prohibition, it becomes a Source rules line that states the prohibition for any non-user source (D3). For example, the capital stack's line becomes: "Tranche amounts and terms are user-supplied capital terms; a block whose source is not manual, user or wizard MUST NOT state a tranche rate, amount or a stated sizing value."
5. Provenance identities (D2). The generic agent/<id> source namespace, its required agent_id and agent_version, and the free-form actor stay as they are (Format §2.5–§2.6, Part III). Only the retired agent host layer ids leave the spec's examples and prose (agent/L6-01 becomes, for example, agent/risk-rater).
6. Format Part VI (Toolchain Interface) moves to the non-normative starter guide as the CLI reference, without uwmd run (D6). §6.8's obligations are sorted (D5): the producer rules move into Part III, and the product mechanics are dropped.
7. Format Part VII (Rendering Targets) moves to the starter guide as the renderer reference (D6).
8. Module manifests. agent_layers, ModuleAgentLayerDecl and prompt_template are removed from spec/schemas/module-manifest.schema.json, protocol.ts and Protocol Appendix F. Manifests already refuse unknown members, so a manifest that still declares agent_layers is refused. The codes that validated it (PROTO-MOD-055 to PROTO-MOD-060) are retired and stay reserved (D7).
9. Protocol §II.4. The agent-host capability flag is removed from the starter-product capability list and ImplementationManifest.capabilities, because no starter product hosts agents.
10. Reference library. BANCROFT_LAYERS, the layer context, prompt and readiness builders, LayerDefinition/AgentContext/retired agent hostPrompt and uwmd layers are removed with the vocabulary they implement. The generic writers (writeAgentBlock, writeErrorEntry, buildMeta) and generic buildContext stay.

Compatibility analysis

No compatibility path (prelaunch; the owner rule). Records that carry pipeline_state keep reading (D4). Module manifests that declare agent_layers are refused. Examples, fixtures and baselines are rewritten.

Conformance impact

• Examples and fixtures drop pipeline_state and take neutral agent ids. Their integrity hashes, signatures and expected outputs are regenerated.
• Module fixture 02-agent-layer-malformed and any agent_layers cases are retired. A new refusal case shows that a manifest declaring agent_layers is refused as an unknown member.
• Capability fixtures stop listing agent-host.
• No financial expected result changes.

Reference implementation

In the implementation PR after acceptance: the Format and Protocol edits above; the schema, protocol.ts and modules.ts changes in lockstep (invariant 7); the core removals in item 10; the starter-guide pages for the CLI and renderer; corpus regeneration; the Python implementation's manifest and module reader.

Alternatives considered

• Mark §1.3, Part VI and Part VII "historical, non-normative" and keep them. This leaves a removed product in the standard's text. Rejected under D1 ("don't move it").
• Make source fully free-form and drop the agent/* namespace and its agent_id/agent_version requirement (the cleanup brief's wording, "provenance actors become free-form strings"). This removes writer accountability that the repo guidance keeps ("keep provenance, including agent identities"). Not proposed; see D2.
• Keep agent_layers for third-party hosts. No standard tool reads it, and it encodes one product's prompt model. A third-party host can declare its own capability in an x_* extension. Not proposed.

Unresolved questions

• §6.8 item 7 ("never set human_review_required: false when the block contains any low confidence values") has no validator check today. D5 proposes moving it into Part III as a SHOULD for every producer, but it could also be dropped as a product rule.

Decisions (accepted 2026-10-21)

#	Question	Proposal	Why / alternative
D1	Scope	§1.2 sentence, §1.3, pipeline_state, Written-by lines, Part VI, Part VII, agent_layers, agent-host, the layer registry	Every place the standard names the removed suite
D2	Agent identity in provenance	Ruled: Keep agent/<id> with agent_id/agent_version; actor stays free-form; layer ids leave the examples	AGENTS.md keeps agent identities. Alternative: fully free-form sources, as the brief worded it
D3	Written-by prohibitions	Restated as Source rules for any non-user source	Keeps "MUST NOT invent" rules that protect verification
D4	A record that still carries pipeline_state	Not refused; ignored	RFC 0108 D5 (retired spellings not refused). Alternative: refuse it as an unknown member
D5	§6.8 obligations	2–5 (schema, _meta first, revision, superseded: false) move into Part III; 7 becomes a Part III SHOULD; 1, 6 and 8 (read state, layer scope, awaiting_input reply) are dropped as product mechanics	Producer invariants stay; product request/response goes
D6	Part VI and Part VII	Move to docs/starter/ as the CLI and renderer references	RFC 0078: the CLI and renderer are starter products. Alternative: delete them
D7	Retired module codes	Reserved, never reused	Release rule (b), ratified 2026-10-21
D8	Versions	None allocated; prelaunch 4.x	RFC 0091 D6

Prior art

• RFC 0078 (the standard is verification; agents and the CLI are starter products; the Agent Host tier is retired).
• RFC 0108 D5 (retired members are not refused when nothing reads them).
• docs/reviews/2026-10-15-agent-removal-5.0.md, which sorted the §6.8 obligations and the call sites.