refactor(acr): ACR Store 1 as a disposable memo, not a durable side-store (#305)

The shipped Store 1 persisted repo-file descriptors in a new SqliteObservationStore
— a second, unsynchronized SQLite writer on the event-log DB (no WAL/busy_timeout,
one shared Connection across coroutines) holding a fact the log already carries. That
violates "the event log is the only source of truth" (inv #1/#8): an Observation is
just FileWrittenEvent.path + postImageHash + describe(bytes).render(), and render is a
pure function of content-addressed CAS bytes.

Replace the whole durable apparatus with an in-process memo (descriptorMemo, keyed on
repoRoot+path+contentHash) on the orchestrator, next to the existing artifactContentCache.
Rebuilt from the log on restart, disposable, no external store. Preserves the perf win
(skip CAS read + regex on repeat describes) with none of the concurrency/lock risk.

Deletes: ObservationStore/InMemoryObservationStore/SqliteObservationStore (+ tests),
InfrastructureModule.createObservationStore, the FileReadTool priming path (which never
hit anyway — it keyed on a workspace-relative path while every consumer looks up the
absolute FileWrittenEvent.path), the FileReadConfig/SessionOrchestrator plumbing, and
five orphaned build.gradle deps.

Store 2 (soft-confidence hints) unchanged — it was correct.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HMbPmZZjcXhR2crU82zZ8S

apps/server/src/main/kotlin/com/correx/apps/server/Main.kt

@@ -344,12 +344,9 @@ fun main() {
         ),
     )
 
-    val observationStore = InfrastructureModule.createObservationStore()
     val wsToolRegistryProvider = WorkspaceToolRegistryProvider { workspace ->
         val wsRegistry = InfrastructureModule.createToolRegistry(
-            buildToolConfigForWorkspace(
+            buildToolConfigForWorkspace(workspace, shellAllowedExecutables, toolsConfig, researchToolConfig),
-                workspace, shellAllowedExecutables, toolsConfig, researchToolConfig, observationStore,
-            ),
             extraTools = extraTools,
         )
         val wsExecutor = DispatchingToolExecutor(wsRegistry)
@@ -499,7 +496,6 @@ fun main() {
         compactionService = journalCompactionService,
         artifactKindRegistry = artifactKindRegistry,
         repoKnowledgeRetriever = repoKnowledgeRetriever,
-        observationStore = observationStore,
         readyTaskCounter = com.correx.apps.server.tasks.ProjectReadyTaskCounter(taskService),
         taskClaimCoordinator = com.correx.apps.server.tasks.DefaultTaskClaimCoordinator(
             taskService,
@@ -965,7 +961,6 @@ private fun buildToolConfigForWorkspace(
     shellAllowedExecutables: Set<String>,
     toolsConfig: com.correx.core.config.ToolsConfig,
     research: com.correx.infrastructure.tools.ResearchToolConfig,
-    observationStore: com.correx.core.context.observation.ObservationStore? = null,
 ): ToolConfig = ToolConfig(
     research = research,
     shell = ShellConfig(
@@ -977,8 +972,6 @@ private fun buildToolConfigForWorkspace(
         enabled = toolsConfig.fileReadEnabled,
         allowedPaths = workspace.allowedPaths,
         workingDir = workspace.workingDir,
-        observationStore = observationStore,
-        repoRoot = workspace.workingDir?.toString(),
     ),
     fileWrite = FileWriteConfig(
         enabled = toolsConfig.fileWriteEnabled,

core/context/src/main/kotlin/com/correx/core/context/observation/ObservationStore.kt

@@ -1,36 +0,0 @@
-package com.correx.core.context.observation
-
-import java.util.concurrent.ConcurrentHashMap
-
-/**
- * ACR Store 1 (docs/plans/2026-07-21-acr-knowledge-accretion.md): a fact about a repo file,
- * keyed on (repoRoot, path) — task-agnostic, any future run benefits. [contentHash] is the
- * staleness check: a caller re-validates by hash before trusting [descriptorRender], per
- * invariant #9 (never re-derive from a re-observed environment when the prior observation still
- * holds). [descriptorRender] is [com.correx.core.sourcedesc.SourceDescriptor.render] output — the
- * only thing every current call site actually consumes, so that's what's stored, not the object.
- */
-data class Observation(
-    val repoRoot: String,
-    val path: String,
-    val contentHash: String,
-    val descriptorRender: String?,
-    val observedAtMs: Long,
-)
-
-interface ObservationStore {
-    suspend fun get(repoRoot: String, path: String): Observation?
-    suspend fun put(observation: Observation)
-}
-
-/** Default/test backend — process-lifetime only. Production wiring swaps in a durable store. */
-class InMemoryObservationStore : ObservationStore {
-    private val entries = ConcurrentHashMap<Pair<String, String>, Observation>()
-
-    override suspend fun get(repoRoot: String, path: String): Observation? =
-        entries[repoRoot to path]
-
-    override suspend fun put(observation: Observation) {
-        entries[observation.repoRoot to observation.path] = observation
-    }
-}

core/context/src/test/kotlin/com/correx/core/context/observation/InMemoryObservationStoreTest.kt

@@ -1,43 +0,0 @@
-package com.correx.core.context.observation
-
-import kotlinx.coroutines.runBlocking
-import kotlin.test.Test
-import kotlin.test.assertEquals
-import kotlin.test.assertNull
-
-class InMemoryObservationStoreTest {
-
-    @Test
-    fun `put then get returns the stored observation`(): Unit = runBlocking {
-        val store = InMemoryObservationStore()
-        val obs = Observation("repoA", "src/Foo.kt", "hash1", "module=foo", 100L)
-
-        store.put(obs)
-
-        assertEquals(obs, store.get("repoA", "src/Foo.kt"))
-    }
-
-    @Test
-    fun `same path in different repos does not collide`(): Unit = runBlocking {
-        val store = InMemoryObservationStore()
-        store.put(Observation("repoA", "src/Foo.kt", "hashA", "a", 1L))
-        store.put(Observation("repoB", "src/Foo.kt", "hashB", "b", 2L))
-
-        assertEquals("hashA", store.get("repoA", "src/Foo.kt")?.contentHash)
-        assertEquals("hashB", store.get("repoB", "src/Foo.kt")?.contentHash)
-    }
-
-    @Test
-    fun `put overwrites the prior observation for the same key`(): Unit = runBlocking {
-        val store = InMemoryObservationStore()
-        store.put(Observation("repoA", "src/Foo.kt", "hash1", "old", 1L))
-        store.put(Observation("repoA", "src/Foo.kt", "hash2", "new", 2L))
-
-        assertEquals("hash2", store.get("repoA", "src/Foo.kt")?.contentHash)
-    }
-
-    @Test
-    fun `unknown key returns null`(): Unit = runBlocking {
-        assertNull(InMemoryObservationStore().get("repoA", "nope"))
-    }
-}

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/DefaultSessionOrchestrator.kt

@@ -7,7 +7,6 @@ import com.correx.core.inference.Tokenizer
 import com.correx.core.journal.DefaultDecisionJournalRepository
 import com.correx.core.artifacts.kind.ArtifactKindRegistry
 import com.correx.core.artifactstore.ArtifactStore
-import com.correx.core.context.observation.ObservationStore
 import com.correx.core.events.events.ApprovalDecisionResolvedEvent
 import com.correx.core.events.events.ArtifactContentStoredEvent
 import com.correx.core.events.events.ClarificationAnswer
@@ -112,8 +111,7 @@ class DefaultSessionOrchestrator(
     readyTaskCounter: ReadyTaskCounter? = null,
     taskClaimCoordinator: TaskClaimCoordinator? = null,
     tuning: OrchestrationTuning = OrchestrationTuning(),
-    observationStore: ObservationStore? = null,
+) : SessionOrchestrator(repositories, engines, artifactStore, decisionJournalRepository, artifactKindRegistry = artifactKindRegistry, repoKnowledgeRetriever = repoKnowledgeRetriever, readyTaskCounter = readyTaskCounter, taskClaimCoordinator = taskClaimCoordinator, tuning = tuning), ApprovalGateway {
-) : SessionOrchestrator(repositories, engines, artifactStore, decisionJournalRepository, artifactKindRegistry = artifactKindRegistry, repoKnowledgeRetriever = repoKnowledgeRetriever, readyTaskCounter = readyTaskCounter, taskClaimCoordinator = taskClaimCoordinator, tuning = tuning, observationStore = observationStore), ApprovalGateway {
     override val tokenizer: Tokenizer? = tokenizer
     override val cancellations: ConcurrentHashMap<SessionId, AtomicBoolean> =
         ConcurrentHashMap<SessionId, AtomicBoolean>()

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/SessionOrchestrator.kt

@@ -8,7 +8,6 @@ import com.correx.core.artifacts.kind.KindInference
 import com.correx.core.artifactstore.ArtifactStore
 import com.correx.core.context.builder.ContextPackBuilder
 import com.correx.core.context.model.ContextPack
-import com.correx.core.context.observation.ObservationStore
 import com.correx.core.events.events.ClarificationAnswer
 import com.correx.core.events.events.ClarificationAnsweredEvent
 import com.correx.core.events.events.ClarificationRequestedEvent
@@ -203,7 +202,6 @@ abstract class SessionOrchestrator(
     internal val readyTaskCounter: ReadyTaskCounter? = null,
     internal val taskClaimCoordinator: TaskClaimCoordinator? = null,
     internal val tuning: OrchestrationTuning = OrchestrationTuning(),
-    internal val observationStore: ObservationStore? = null,
 ) {
     internal val log = LoggerFactory.getLogger(this::class.java)
     internal val eventStore: EventStore = repositories.eventStore
@@ -250,6 +248,11 @@ abstract class SessionOrchestrator(
      */
     internal val artifactContentCache: ConcurrentHashMap<String, String> = ConcurrentHashMap()
 
+    // ACR Store 1: in-process memo of describe().render(), keyed on (repoRoot, path, contentHash).
+    // Disposable — the source of truth is FileWrittenEvent + CAS; this only skips recomputing a pure
+    // function of content-addressed bytes. Empty string = a computed "no descriptor" (negative cache).
+    internal val descriptorMemo: ConcurrentHashMap<String, String> = ConcurrentHashMap()
+
     /** Drops a terminated session's cached artifact contents (the heaviest per-session state — full
      *  file/JSON payloads). Safe: rehydrateArtifactContentCache rebuilds it from durable events if the
      *  session is ever resumed. Called on WorkflowCompleted/WorkflowFailed. */

infrastructure/build.gradle

@@ -12,7 +12,6 @@ dependencies {
     implementation project(":core:approvals")
     implementation project(":core:sessions")
     implementation project(":core:config")
-    implementation project(":core:context")
     implementation project(":infrastructure:inference")
     implementation project(":infrastructure:inference:commons")
     implementation project(":infrastructure:inference:llama_cpp")

infrastructure/persistence/build.gradle

@@ -10,7 +10,6 @@ dependencies {
     implementation(project(":core:sessions"))
     implementation(project(":core:artifacts"))
     implementation(project(":core:artifacts-store"))
-    implementation(project(":core:context"))
     implementation "org.xerial:sqlite-jdbc"
     implementation "org.slf4j:slf4j-api:2.0.16"
     testImplementation(testFixtures(project(":testing:contracts")))

infrastructure/persistence/src/main/kotlin/com/correx/infrastructure/persistence/observation/SqliteObservationStore.kt

@@ -1,76 +0,0 @@
-package com.correx.infrastructure.persistence.observation
-
-import com.correx.core.context.observation.Observation
-import com.correx.core.context.observation.ObservationStore
-import com.correx.infrastructure.persistence.util.JDBCHelper.transaction
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.withContext
-import java.sql.Connection
-
-/**
- * Durable backend for ACR Store 1 (docs/plans/2026-07-21-acr-knowledge-accretion.md), so
- * observations survive a server restart the way the event log itself does. One row per
- * (repo_root, path); a `put` overwrites the prior observation for that key outright — this store
- * only ever holds the latest fact, staleness is resolved by the caller comparing content_hash.
- */
-class SqliteObservationStore(private val connection: Connection) : ObservationStore {
-
-    init {
-        connection.createStatement().use { stmt ->
-            stmt.execute(
-                """
-                CREATE TABLE IF NOT EXISTS observations (
-                    repo_root TEXT NOT NULL,
-                    path TEXT NOT NULL,
-                    content_hash TEXT NOT NULL,
-                    descriptor_render TEXT,
-                    observed_at_ms INTEGER NOT NULL,
-                    PRIMARY KEY (repo_root, path)
-                )
-                """.trimIndent(),
-            )
-        }
-    }
-
-    override suspend fun get(repoRoot: String, path: String): Observation? = withContext(Dispatchers.IO) {
-        connection.prepareStatement(
-            "SELECT content_hash, descriptor_render, observed_at_ms FROM observations " +
-                "WHERE repo_root = ? AND path = ?",
-        ).use { stmt ->
-            stmt.setString(1, repoRoot)
-            stmt.setString(2, path)
-            stmt.executeQuery().use { rs ->
-                if (!rs.next()) return@withContext null
-                Observation(
-                    repoRoot = repoRoot,
-                    path = path,
-                    contentHash = rs.getString("content_hash"),
-                    descriptorRender = rs.getString("descriptor_render"),
-                    observedAtMs = rs.getLong("observed_at_ms"),
-                )
-            }
-        }
-    }
-
-    @Suppress("MagicNumber") // JDBC positional parameter indices, not data
-    override suspend fun put(observation: Observation) = withContext(Dispatchers.IO) {
-        connection.transaction {
-            connection.prepareStatement(
-                "INSERT INTO observations (repo_root, path, content_hash, descriptor_render, observed_at_ms) " +
-                    "VALUES (?, ?, ?, ?, ?) " +
-                    "ON CONFLICT(repo_root, path) DO UPDATE SET " +
-                    "content_hash = excluded.content_hash, " +
-                    "descriptor_render = excluded.descriptor_render, " +
-                    "observed_at_ms = excluded.observed_at_ms",
-            ).use { stmt ->
-                stmt.setString(1, observation.repoRoot)
-                stmt.setString(2, observation.path)
-                stmt.setString(3, observation.contentHash)
-                stmt.setString(4, observation.descriptorRender)
-                stmt.setLong(5, observation.observedAtMs)
-                stmt.executeUpdate()
-            }
-        }
-        Unit
-    }
-}

infrastructure/persistence/src/test/kotlin/com/correx/infrastructure/persistence/observation/SqliteObservationStoreTest.kt

@@ -1,37 +0,0 @@
-package com.correx.infrastructure.persistence.observation
-
-import com.correx.core.context.observation.Observation
-import kotlinx.coroutines.runBlocking
-import java.sql.DriverManager
-import kotlin.test.Test
-import kotlin.test.assertEquals
-import kotlin.test.assertNull
-
-class SqliteObservationStoreTest {
-
-    private fun store() = SqliteObservationStore(DriverManager.getConnection("jdbc:sqlite::memory:"))
-
-    @Test
-    fun `put then get round-trips through sqlite`(): Unit = runBlocking {
-        val store = store()
-        store.put(Observation("repoA", "src/Foo.kt", "hash1", "module=foo", 100L))
-
-        val fetched = store.get("repoA", "src/Foo.kt")
-
-        assertEquals(Observation("repoA", "src/Foo.kt", "hash1", "module=foo", 100L), fetched)
-    }
-
-    @Test
-    fun `put overwrites the prior row for the same key`(): Unit = runBlocking {
-        val store = store()
-        store.put(Observation("repoA", "src/Foo.kt", "hash1", "old", 1L))
-        store.put(Observation("repoA", "src/Foo.kt", "hash2", "new", 2L))
-
-        assertEquals("hash2", store.get("repoA", "src/Foo.kt")?.contentHash)
-    }
-
-    @Test
-    fun `unknown key returns null`(): Unit = runBlocking {
-        assertNull(store().get("repoA", "nope"))
-    }
-}

infrastructure/src/main/kotlin/com/correx/infrastructure/InfrastructureModule.kt

@@ -53,10 +53,8 @@ import io.ktor.client.HttpClient
 import io.ktor.client.engine.cio.CIO
 import com.correx.infrastructure.router.turbovec.TurboVecL3MemoryStore
 import com.correx.infrastructure.router.turbovec.TurboVecSidecarConfig
-import com.correx.core.context.observation.ObservationStore
 import com.correx.infrastructure.persistence.SqliteEventStore
 import com.correx.infrastructure.persistence.artifact.LiveArtifactRepository
-import com.correx.infrastructure.persistence.observation.SqliteObservationStore
 import com.correx.infrastructure.tools.DefaultToolRegistry
 import com.correx.infrastructure.tools.DispatchingToolExecutor
 import com.correx.infrastructure.tools.SandboxedToolExecutor
@@ -108,12 +106,6 @@ object InfrastructureModule {
         )
     }
 
-    fun createObservationStore(dbPath: String = defaultDbPath): ObservationStore {
-        val dir = java.io.File(dbPath).parentFile
-        if (!dir.exists()) dir.mkdirs()
-        return SqliteObservationStore(DriverManager.getConnection("jdbc:sqlite:$dbPath"))
-    }
-
     fun createArtifactStore(rootDir: Path = Paths.get(defaultArtifactsRoot)): ArtifactStore {
         Files.createDirectories(rootDir)
         val index = SqliteArtifactIndex(rootDir.resolve("index.sqlite"))

infrastructure/tools/build.gradle

@@ -17,7 +17,6 @@ dependencies {
     implementation project(":infrastructure:tools:filesystem")
     implementation project(":core:artifacts")
     implementation project(":core:artifacts-store")
-    implementation project(":core:context")
 
     // Web research tools (web_search, web_fetch) + deterministic HTML→markdown extraction.
     implementation 'org.jsoup:jsoup:1.20.1'

infrastructure/tools/filesystem/build.gradle

@@ -10,8 +10,6 @@ dependencies {
     implementation project(':core:approvals')
     implementation project(':core:artifacts')
     implementation project(':core:artifacts-store')
-    implementation project(':core:context')
-    implementation project(':core:sourcedesc')
     implementation 'org.slf4j:slf4j-api:2.0.16'
 }
 

infrastructure/tools/filesystem/src/main/kotlin/com/correx/infrastructure/tools/filesystem/FileReadTool.kt

@@ -1,10 +1,7 @@
 package com.correx.infrastructure.tools.filesystem
 
 import com.correx.core.approvals.Tier
-import com.correx.core.context.observation.Observation
-import com.correx.core.context.observation.ObservationStore
 import com.correx.core.events.events.ToolRequest
-import com.correx.core.sourcedesc.describe
 import com.correx.core.tools.compression.CompressionRule.StripBlankLines
 import com.correx.core.tools.compression.CompressionRule.StripLeadingWhitespace
 import com.correx.core.tools.compression.DeclarativeCompressor
@@ -35,12 +32,6 @@ import kotlin.io.path.name
 class FileReadTool(
     private val allowedPaths: Set<Path> = emptySet(),
     private val workingDir: Path? = null,
-    // ACR Store 1 (docs/plans/2026-07-21-acr-knowledge-accretion.md): primes the cross-session
-    // observation cache on a whole-file read, not just on write, so a later describeCached lookup
-    // (SessionOrchestratorArtifacts.kt) for this exact content hash is already warm. Both null by
-    // default — no-op unless a workspace wiring supplies them.
-    private val observationStore: ObservationStore? = null,
-    private val repoRoot: String? = null,
 ) : Tool, ToolExecutor {
 
     // Resolve relative paths against the bound workspace's working dir, NOT the JVM
@@ -149,7 +140,7 @@ class FileReadTool(
         }
     }
 
-    private suspend fun readFile(path: Path, startLine: Int?, endLine: Int?, request: ToolRequest): ToolResult = runCatching {
+    private fun readFile(path: Path, startLine: Int?, endLine: Int?, request: ToolRequest): ToolResult = runCatching {
         // Read the file once. Lines and the (whole-read) content hash both derive from these bytes,
         // so a full read no longer hits the disk twice (readAllLines + readAllBytes for the hash).
         val bytes = Files.readAllBytes(path)
@@ -178,9 +169,7 @@ class FileReadTool(
         // against what the agent actually saw. A partial or truncated view establishes no baseline —
         // the agent must read the relevant range before editing.
         val sawWholeFile = startLine == null && endLine == null && !lineCapped && !charCapped
-        val hash = if (sawWholeFile) sha256(bytes) else null
+        val metadata = if (sawWholeFile) mapOf("contentHash" to sha256(bytes)) else emptyMap()
-        val metadata = hash?.let { mapOf("contentHash" to it) } ?: emptyMap()
-        hash?.let { primeObservation(path, bytes, it) }
         ToolResult.Success(
             invocationId = request.invocationId,
             output = content + note,
@@ -194,17 +183,6 @@ class FileReadTool(
         )
     }
 
-    /** No-op unless both [observationStore] and [repoRoot] are wired; skips if already cached for this hash. */
-    private suspend fun primeObservation(path: Path, bytes: ByteArray, hash: String) {
-        val store = observationStore ?: return
-        val root = repoRoot ?: return
-        val relPath = workingDir?.let { runCatching { it.relativize(path).toString() }.getOrNull() } ?: path.toString()
-        val cached = store.get(root, relPath)
-        if (cached?.contentHash == hash) return
-        val rendered = describe(relPath, bytes).render().takeIf { it.isNotBlank() }
-        store.put(Observation(root, relPath, hash, rendered, System.currentTimeMillis()))
-    }
-
     private fun sha256(bytes: ByteArray): String =
         java.security.MessageDigest.getInstance("SHA-256").digest(bytes)
             .joinToString("") { "%02x".format(it) }

infrastructure/tools/filesystem/src/test/kotlin/com/correx/infrastructure/tools/filesystem/FileReadToolTest.kt

@@ -1,6 +1,5 @@
 package com.correx.infrastructure.tools.filesystem
 
-import com.correx.core.context.observation.InMemoryObservationStore
 import com.correx.core.events.events.ToolRequest
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
@@ -194,24 +193,6 @@ class FileReadToolTest {
         assertTrue((result as ToolResult.Success).metadata["contentHash"] != null)
     }
 
-    @Test
-    fun `execute primes the observation store for a whole-file read`(): Unit = runBlocking {
-        val tempFile = Files.createTempFile("test_prime", ".kt")
-        Files.writeString(tempFile, "fun foo() {}")
-        val store = InMemoryObservationStore()
-        val tool = FileReadTool(
-            allowedPaths = setOf(tempFile.parent),
-            workingDir = tempFile.parent,
-            observationStore = store,
-            repoRoot = "repoA",
-        )
-
-        tool.execute(createRequest(tempFile.toString()))
-
-        val observed = store.get("repoA", tempFile.fileName.toString())
-        assertTrue(observed != null)
-    }
-
     @Test
     fun `outputCompressor strips blank lines and leading whitespace`() {
         val tool = FileReadTool()

infrastructure/tools/src/main/kotlin/com/correx/infrastructure/tools/ToolConfig.kt

@@ -1,6 +1,5 @@
 package com.correx.infrastructure.tools
 
-import com.correx.core.context.observation.ObservationStore
 import com.correx.core.tools.contract.Tool
 import com.correx.infrastructure.tools.filesystem.FileDeleteTool
 import com.correx.infrastructure.tools.filesystem.FileEditTool
@@ -40,9 +39,6 @@ data class FileReadConfig(
     val enabled: Boolean = false,
     val allowedPaths: Set<Path> = emptySet(),
     val workingDir: Path? = null,
-    // ACR Store 1 hot-path priming (docs/plans/2026-07-21-acr-knowledge-accretion.md); both null is a no-op.
-    val observationStore: ObservationStore? = null,
-    val repoRoot: String? = null,
 )
 data class FileWriteConfig(
     val enabled: Boolean = false,
@@ -79,8 +75,6 @@ fun ToolConfig.buildTools(): List<Tool> = buildList {
             FileReadTool(
                 allowedPaths = fileRead.allowedPaths,
                 workingDir = fileRead.workingDir,
-                observationStore = fileRead.observationStore,
-                repoRoot = fileRead.repoRoot,
             ),
         )
         // list_dir is read-only enumeration; shares the reader's jail + anchor and the same toggle.