Phase 0: establish final admission contracts

[johnnygreco]

Objective

Establish the final harness-admission names/contracts, remove superseded receipt and Pi-specific compatibility paths, pin the actual fork contract, and add real multi-turn provider fixtures before broader hooks are added.

Context

• Tracker: GitHub goal delivery: close Pi attested-admission gaps #50
• The current system admits user messages and tool results, then re-admits the newest entry at send time. This phase is naming/contract hygiene only; later phases add origins and whole-context binding.
• Initial heads: Research c7b757d, Pi 61500e60, OpenShell 8332c459.

Scope

• In scope, Research: rename hooks to user_message/tool_result; --require-agent-attestation; registry-based binding resolution; openshell.pi-message.v1 with required origin=user; PiMessageV1Adapter; remove ReceiptClaimsV1, one-use receipt APIs/state, extension-v1, and obsolete receipt reason names; correct middleware manifest proto source/hash/note; add multi-turn Chat Completions, Responses, and Qwen fixtures and strict-schema decisions; mark the managed-harness ledger plan superseded.
• In scope, OpenShell: remove LEGACY_PI_BRIDGE_URL_ENV and provider-env insertion.
• In scope, workspace: archive the uncommitted /home/ubuntu/workspaces/2/pi-egress-fork design to explore/prepare-context-hook in the Pi fork with a clear note, verify the remote branch, then remove only that archived checkout.
• Non-goals: new append origins, attestation v2, base64 bridge bodies, caller identity, upstream rebases.
• Backward compatibility: not required; do not add aliases/shims.
• Dependencies: none.
• Sequencing: first.

Implementation Notes

• Keep harness=pi as registry data, never a servicer literal check.
• Keep the reserved receipt header defense but use reserved_header_present.
• Do not modify the protobuf.
• Existing draft PRs remain the reviewer surfaces: Research feat(egress-gate): add attested Pi prompt admission #38, feat(supervisor): add managed Pi admission bridge johnnygreco/OpenShell#1, feat(coding-agent): add user message append hook johnnygreco/pi#1.
• Agents working in parallel must own separate repositories/file sets.

Acceptance Criteria

• Final names appear consistently in code, tests, example, manifest, and current docs.
• Superseded receipt APIs/state and legacy bridge environment variable are absent outside historical material.
• Multi-turn fixtures cover assistant tool calls/tool replies, Qwen reasoning content, Responses reasoning/function calls, and compaction-summary replay.
• Strictly rejected fields have an explicit fixture/test decision.
• The alternate prototype is recoverably archived before its checkout is removed.

Required Validation

• Research: cd projects/egress-gate && make check && make check-py311
• OpenShell: mise run pre-commit, focused cargo test -p openshell-sandbox, then mise run test/mise run ci before review.
• Acceptance grep for pi-input.v1|extension-v1|require_pi_attestation|OPENSHELL_PI_CONVERSATION_URL across current code.

PR Expectations

Keep changes grouped into phase-specific commits. Reviewer notes must call out fixture provenance and every deleted compatibility path. No generated protobuf diff is expected.

[johnnygreco]

Work started on the reviewed branch heads:

• Research johnny/pi-attested-admission at c7b757d
• Pi johnny/before-user-message-commit at 61500e60
• OpenShell openshell/pi-egress-admission at 8332c459

Parallel ownership for this phase is repository-separated: Research contract/fixture hygiene, OpenShell legacy bridge cleanup, and recoverable archival of the stray Pi prototype. Upstream refresh is explicitly deferred to final integration because it would introduce unrelated churn and Pi forbids force-pushes.

[johnnygreco]

Phase 0 implementation and review are complete across the existing draft PRs.

• Research PR feat(egress-gate): add attested Pi prompt admission #38: 8910d79 plus canonical-envelope fix cc8497e; independent re-review clean.
• OpenShell fork PR Add Reachy Mini OpenShell demo project #1: 9ac8f8db and 5f542b70; independent re-review clean.
• Pi archive: prototype preserved at johnnygreco/pi branch explore/prepare-context-hook, commit b7d3f772; stray checkout removed only after remote SHA verification.
• No active Pi feature-branch changes were required for Phase 0.

Acceptance criteria are satisfied. Required validation passed except OpenShell's full mise run ci, which reached a pre-existing unrelated Go converter coverage failure for ProviderProfileCredential.delivery; Phase 0 touched no Go or protobuf files. mise run pre-commit, mise run test, and focused sandbox tests passed.

Review evidence: Research PR Review Record and OpenShell PR Review Record are posted on their respective existing draft PRs. No new implementation PRs were opened.