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# Session 01: Contracts And Naming Baseline

**Session ID**: `phase09-session01-contracts-and-naming-baseline` **Package**: packages/protocol **Status**: Not Started **Estimated Tasks**: \~14-20 **Estimated Duration**: 2-4 hours

***

## Objective

Add Codex CLI and provider-neutral naming support to shared contracts without changing Claude Code behavior.

***

## Scope

### In Scope (MVP)

* Add `codex-cli` protocol support.
* Rename provider-neutral ingest constants with backward-compatible aliases.
* Add Codex event names and safe optional fields.
* Add focused protocol tests.
* Update source comments that block provider-neutral behavior.

### Detailed Requirements

* Add `"codex-cli"` to `HeroCli` in `packages/protocol/src/heroes.ts`.
* Add display metadata helpers if web code currently duplicates CLI labels.
* Rename `CLAUDE_HOOK_EVENT_NAMES` to `AGENT_HOOK_EVENT_NAMES` or `FACTIONOS_HOOK_EVENT_NAMES` and keep a deprecated Claude alias.
* Add Codex lifecycle events: `SubagentStart`, `PreCompact`, and `PostCompact`.
* Add optional safe Codex fields: `turnId`, `permissionMode`, `hookEventName`, `agentId`, `agentType`, `toolName`, and compact `mcpToolName`.
* Keep `transcript_path` and `transcriptPath` out of promoted event payloads except as local-only handler input for safe ID derivation.
* Preserve `/event` compatibility with `eventName ?? hook` payloads and type-only compatibility inputs.

### Out of Scope

* CLI Codex installation.
* Server, web, or hook runtime behavior changes beyond compile-time contract consumers required by the protocol update.
* Custom Codex slash command claims.

***

## Prerequisites

* [ ] Phase 08 complete.
* [ ] Codex integration plan reviewed.
* [ ] Current protocol event and hero contracts reviewed.

***

## Deliverables

1. Shared protocol support for `codex-cli`.
2. Backward-compatible provider-neutral names and aliases.
3. Codex hook event shape additions with bounded optional fields.
4. Focused tests proving Claude compatibility and Codex contract acceptance.
5. Source comments updated where Claude-only language blocks provider-neutral behavior.

***

## Success Criteria

* [ ] Typecheck and protocol tests pass.
* [ ] No Claude behavior changes beyond names and aliases.
* [ ] No raw prompt, transcript, patch, command output, MCP args, token, or path fields become required shared payloads.


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