feat: expand message ref format from 4-digit to 5-digit (9999→99999)

AGENTS.md

@@ -52,7 +52,7 @@ opencode-acp/
 │   ├── logger.ts                     # Structured logging (logs/acp/)
 │   ├── auth.ts                       # Plugin authentication
 │   ├── token-utils.ts                # Token counting utilities
-│   ├── message-ids.ts                # Message ID mapping (raw ↔ mNNNN refs)
+│   ├── message-ids.ts                # Message ID mapping (raw ↔ mNNNNNN refs)
 │   ├── compress-permission.ts        # Permission management for compress tool
 │   ├── protected-patterns.ts         # File pattern protection logic
 │   ├── host-permissions.ts           # Host-based permission system
@@ -160,14 +160,14 @@ index.ts (Plugin Entry — registers hooks + tools)
     ├─► Message Transform Hook (experimental.chat.messages.transform) ← runs EVERY LLM call
     │       │
     │       ├─► checkSession() → state init, load persisted state
-    │       ├─► stripHallucinations() → remove stale mNNNN refs from model output
-    │       ├─► assignMessageRefs() → bidirectional map: raw message IDs ↔ mNNNN refs
+    │       ├─► stripHallucinations() → remove stale mNNNNN refs from model output
+    │       ├─► assignMessageRefs() → bidirectional map: raw message IDs ↔ mNNNNN refs
     │       ├─► syncCompressionBlocks() → deactivate orphaned blocks (messages deleted externally)
     │       ├─► runMajorGC() → age-based block deactivation + truncate oversized summaries
     │       ├─► prune() → replace compressed ranges with summary blocks in messages
     │       ├─► injectCompressNudges() → add context-limit / turn / iteration nudges
     │       │       └─► includes block aging guidance (only when context usage > 50%)
-    │       ├─► injectMessageIds() → tag every message with mNNNN ref (or BLOCKED)
+    │       ├─► injectMessageIds() → tag every message with mNNNNN ref (or BLOCKED)
     │       ├─► applyAnchoredNudges() → render nudge text into actual messages
     │       └─► stripStaleMetadata() → clean up removed messages' metadata
     │
@@ -179,7 +179,7 @@ index.ts (Plugin Entry — registers hooks + tools)
     │       └─► Track compress tool start/complete → attach duration to blocks
     │
     ├─► Text Complete Hook (experimental.text.complete)
-    │       └─► Strip hallucinated mNNNN/bN refs from completions
+    │       └─► Strip hallucinated mNNNNN/bN refs from completions
     │
     └─► Compress Tool (registered as "compress")
             │
@@ -469,6 +469,19 @@ For reference when modifying code — these bugs were real and the fixes are loa
 3. Understand the module dependency graph (Section 4.1)
 4. Check if the change affects backward compatibility (Section 2.6)
 
+### 5.1.1 Development Workflow
+
+All changes MUST follow this workflow:
+
+1. Create a feature branch from `master`
+2. Implement changes
+3. Ensure `npm run build` and `npm run typecheck` pass
+4. Ensure all tests pass: `npm run test`
+5. Commit with descriptive messages
+6. Push branch and create a GitHub PR
+7. Obtain **dual-agent review** (Sections 5.3 + 5.4) on the PR
+8. Merge PR after both reviews pass
+
 ### 5.2 After Making Changes
 
 1. `npm run build` must pass
@@ -477,17 +490,35 @@ For reference when modifying code — these bugs were real and the fixes are loa
 4. Deploy locally and test in opencode
 5. Update version in `package.json` before publishing
 
-### 5.3 Commit Convention
+### 5.3 Code Review (MANDATORY)
+
+All source code changes (files under `lib/`) MUST undergo independent review by **at least 2 separate agents** before merge. This applies to:
+
+- New modules added to `lib/`
+- Modified source files
+- Changes to shared types, interfaces, or exports
+
+**Review checklist:**
+
+| Category | What to Check |
+|----------|---------------|
+| **Correctness** | Logic matches intent, no off-by-one errors, edge cases handled |
+| **Backward compatibility** | No breaking changes to persisted state format, exported APIs, or internal tags (Section 2.6) |
+| **Performance** | No unnecessary CPU/memory overhead, no O(n²) where O(n) suffices |
+| **Type safety** | No `as any`, no `@ts-ignore`, no type assertion hacks |
+| **State integrity** | State mutations are safe, no lost data on save/load cycle |
+
+### 5.4 Commit Convention
 
 Use descriptive commit messages. Historical examples:
 - `fix: aging warning only shows when context usage > 50%`
 - `feat: /dcp → /acp command rename with backward compat`
 - `chore: bump version to 1.0.1`
 - `fix: config migration moved to getConfig() entry point`
 
-### 5.4 Test Review (MANDATORY)
+### 5.5 Test Review (MANDATORY)
 
-All new and modified test files MUST undergo independent review by **at least 2 separate agents** before being committed. This requirement applies to:
+All new and modified test files MUST undergo independent review by **at least 2 separate agents** before merge (same requirement as Section 5.3 code review). This requirement applies to:
 
 - New test files added to `tests/`
 - Modified test files (changed test logic, not just test names)

lib/compress/message-utils.ts

@@ -88,16 +88,16 @@ const ISSUE_TEMPLATES: Record<string, [singular: string, plural: string]> = {
         "refer to protected messages and cannot be compressed.",
     ],
     "invalid-format": [
-        "is invalid. Use an injected raw message ID of the form mNNNN.",
-        "are invalid. Use injected raw message IDs of the form mNNNN.",
+        "is invalid. Use an injected raw message ID of the form mNNNNN.",
+        "are invalid. Use injected raw message IDs of the form mNNNNN.",
     ],
     "block-id": [
-        "is invalid here. Block IDs like bN are not allowed; use an mNNNN message ID instead.",
-        "are invalid here. Block IDs like bN are not allowed; use mNNNN message IDs instead.",
+        "is invalid here. Block IDs like bN are not allowed; use an mNNNNN message ID instead.",
+        "are invalid here. Block IDs like bN are not allowed; use mNNNNN message IDs instead.",
     ],
     "not-in-context": [
-        "is not available in the current conversation context. Choose an injected mNNNN ID visible in context.",
-        "are not available in the current conversation context. Choose injected mNNNN IDs visible in context.",
+        "is not available in the current conversation context. Choose an injected mNNNNN ID visible in context.",
+        "are not available in the current conversation context. Choose injected mNNNNN IDs visible in context.",
     ],
     protected: [
         "refers to a protected message and cannot be compressed.",

lib/compress/message.ts

@@ -25,7 +25,7 @@ function buildSchema() {
                 tool.schema.object({
                     messageId: tool.schema
                         .string()
-                        .describe("Raw message ID to compress (e.g. m0001)"),
+                        .describe("Raw message ID to compress (e.g. m00001)"),
                     topic: tool.schema
                         .string()
                         .describe("Short label (3-5 words) for this one message summary"),

lib/compress/range.ts

@@ -37,11 +37,11 @@ function buildSchema() {
                     startId: tool.schema
                         .string()
                         .describe(
-                            "Message or block ID marking the beginning of range (e.g. m0001, b2)",
+                            "Message or block ID marking the beginning of range (e.g. m00001, b2)",
                         ),
                     endId: tool.schema
                         .string()
-                        .describe("Message or block ID marking the end of range (e.g. m0012, b5)"),
+                        .describe("Message or block ID marking the end of range (e.g. m00012, b5)"),
                     summary: tool.schema
                         .string()
                         .describe("Complete technical summary replacing all content in range"),

lib/compress/search.ts

@@ -55,11 +55,11 @@ export function resolveBoundaryIds(
     const parsedEndId = parseBoundaryId(endId)
 
     if (parsedStartId === null) {
-        issues.push("startId is invalid. Use an injected message ID (mNNNN) or block ID (bN).")
+        issues.push("startId is invalid. Use an injected message ID (mNNNNN) or block ID (bN).")
     }
 
     if (parsedEndId === null) {
-        issues.push("endId is invalid. Use an injected message ID (mNNNN) or block ID (bN).")
+        issues.push("endId is invalid. Use an injected message ID (mNNNNN) or block ID (bN).")
     }
 
     if (issues.length > 0) {

lib/message-ids.ts

@@ -1,13 +1,13 @@
 import type { SessionState, WithParts } from "./state"
 import { isIgnoredUserMessage } from "./messages/query"
 
-const MESSAGE_REF_REGEX = /^m(\d{4})$/
+const MESSAGE_REF_REGEX = /^m(\d{4,5})$/
 const BLOCK_REF_REGEX = /^b([1-9]\d*)$/
 const MESSAGE_ID_TAG_NAME = "dcp-message-id"
 
-const MESSAGE_REF_WIDTH = 4
+const MESSAGE_REF_WIDTH = 5
 const MESSAGE_REF_MIN_INDEX = 1
-export const MESSAGE_REF_MAX_INDEX = 9999
+export const MESSAGE_REF_MAX_INDEX = 99999
 
 export type ParsedBoundaryId =
     | {
@@ -28,7 +28,7 @@ export function formatMessageRef(index: number): string {
         index > MESSAGE_REF_MAX_INDEX
     ) {
         throw new Error(
-            `Message ID index out of bounds: ${index}. Supported range is 0-${MESSAGE_REF_MAX_INDEX}.`,
+            `Message ID index out of bounds: ${index}. Supported range is ${MESSAGE_REF_MIN_INDEX}-${MESSAGE_REF_MAX_INDEX}.`,
         )
     }
     return `m${index.toString().padStart(MESSAGE_REF_WIDTH, "0")}`

lib/prompts/compress-message.ts

@@ -13,20 +13,20 @@ If a message contains no significant technical decisions, code changes, or user
 MESSAGE IDS
 You specify individual raw messages by ID using the injected IDs visible in the conversation:
 
-- \`mNNNN\` IDs identify raw messages
+- \`mNNNNN\` IDs identify raw messages
 
 Each message has an ID inside XML metadata tags like \`<dcp-message-id priority="high">m0007</dcp-message-id>\`.
 The same ID tag appears in every tool output of the message it belongs to — each unique ID identifies one complete message.
-Treat these tags as message metadata only, not as content to summarize. Use only the inner \`mNNNN\` value as the \`messageId\`.
+Treat these tags as message metadata only, not as content to summarize. Use only the inner \`mNNNNN\` value as the \`messageId\`.
 The \`priority\` attribute indicates relative context cost. You MUST compress high-priority messages when their full text is no longer necessary for the active task.
 If prior compress-tool results are present, always compress and summarize them minimally only as part of a broader compression pass. Do not invoke the compress tool solely to re-compress an earlier compression result.
 Messages marked as \`<dcp-message-id>BLOCKED</dcp-message-id>\` cannot be compressed.
 
 Rules:
 
 - Pick each \`messageId\` directly from injected IDs visible in context.
-- Only use raw message IDs of the form \`mNNNN\`.
-- Ignore XML attributes such as \`priority\` when copying the ID; use only the inner \`mNNNN\` value.
+- Only use raw message IDs of the form \`mNNNNN\`.
+- Ignore XML attributes such as \`priority\` when copying the ID; use only the inner \`mNNNNN\` value.
 - Do not invent IDs. Use only IDs that are present in context.
 
 BATCHING

lib/prompts/compress-range.ts

@@ -18,7 +18,7 @@ Compressed block sections in context are clearly marked with a header:
 
 - \`[Compressed conversation section]\`
 
-Compressed block IDs always use the \`bN\` form (never \`mNNNN\`) and are represented in the same XML metadata tag format.
+Compressed block IDs always use the \`bN\` form (never \`mNNNNN\`) and are represented in the same XML metadata tag format.
 
 Rules:
 
@@ -41,7 +41,7 @@ When you use compressed block placeholders, write the surrounding summary text s
 BOUNDARY IDS
 You specify boundaries by ID using the injected IDs visible in the conversation:
 
-- \`mNNNN\` IDs identify raw messages
+- \`mNNNNN\` IDs identify raw messages
 - \`bN\` IDs identify previously compressed blocks
 
 Each message has an ID inside XML metadata tags like \`<dcp-message-id>...</dcp-message-id>\`.

lib/prompts/extensions/tool.ts

@@ -10,8 +10,8 @@ THE FORMAT OF COMPRESS
   topic: string,           // Short label (3-5 words) - e.g., "Auth System Exploration"
   content: [               // One or more ranges to compress
     {
-      startId: string,     // Boundary ID at range start: mNNNN or bN
-      endId: string,       // Boundary ID at range end: mNNNN or bN
+      startId: string,     // Boundary ID at range start: mNNNNN or bN
+      endId: string,       // Boundary ID at range end: mNNNNN or bN
       summary: string      // Complete technical summary replacing all content in range
     }
   ]
@@ -26,7 +26,7 @@ THE FORMAT OF COMPRESS
   topic: string,           // Short label (3-5 words) for the overall batch
   content: [               // One or more messages to compress independently
     {
-      messageId: string,   // Raw message ID only: mNNNN (ignore metadata attributes like priority)
+      messageId: string,   // Raw message ID only: mNNNNN (ignore metadata attributes like priority)
       topic: string,       // Short label (3-5 words) for this one message summary
       summary: string      // Complete technical summary replacing that one message
     }

lib/state/state.ts

@@ -13,6 +13,7 @@ import {
     collectTurnNudgeAnchors,
 } from "./utils"
 import { getLastUserMessage } from "../messages/query"
+import { parseMessageRef, formatMessageRef } from "../message-ids"
 
 export const checkSession = async (
     client: any,
@@ -195,6 +196,18 @@ export async function ensureSessionInitialized(
                 state.messageIds.byRef.delete(ref)
             }
         }
+        // Migrate 4-digit refs (m0001) to 5-digit (m00001) for msgid expansion
+        for (const [rawId, oldRef] of state.messageIds.byRawId) {
+            const parsed = parseMessageRef(oldRef)
+            if (parsed !== null) {
+                const newRef = formatMessageRef(parsed)
+                if (newRef !== oldRef) {
+                    state.messageIds.byRawId.set(rawId, newRef)
+                    state.messageIds.byRef.delete(oldRef)
+                    state.messageIds.byRef.set(newRef, rawId)
+                }
+            }
+        }
     }
     if (persistedAny._persistedLastCompaction !== undefined) {
         state.lastCompaction = Math.max(state.lastCompaction, persistedAny._persistedLastCompaction)