feat(acr): Store 2 soft-confidence hints + Store 1 FileReadTool priming (#305)

Store 2 (Fixes): ConceptCompilerProjection already tracked the
unconfirmed(validatedFixes>=1)/falsified(contradicted)/confirmed(promoted)
lifecycle as data, but only confirmed (>=threshold) clusters were ever
delivered. unconfirmedFixEntries reactively matches the CURRENT retry's
classKey against that state and injects a soft one-shot hint (below
threshold) or steer-away (contradicted) before hard promotion — wired
into stage context build in SessionOrchestratorExecution.kt.

Store 3 (Plan-shapes): already shipped as SessionOrchestratorPlanPatterns.kt
(deterministic keyword-Jaccard over eventStore.allEvents(), no embedder
needed) — confirmed complete, no new code required.

FileReadTool hot-path extension to Store 1: a whole-file read now primes
the cross-session ObservationStore (when wired) the same way the write
path already does, so a later describeCached lookup for the same content
hash is warm even if the file was only read, not written, this session.

infrastructure/tools/build.gradle

@@ -17,6 +17,7 @@ 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

@@ -10,6 +10,8 @@ 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

@@ -1,7 +1,10 @@
 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
@@ -32,6 +35,12 @@ 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
@@ -140,7 +149,7 @@ class FileReadTool(
         }
     }
 
-    private fun readFile(path: Path, startLine: Int?, endLine: Int?, request: ToolRequest): ToolResult = runCatching {
+    private suspend 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)
@@ -169,7 +178,9 @@ 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 metadata = if (sawWholeFile) mapOf("contentHash" to sha256(bytes)) else emptyMap()
+        val hash = if (sawWholeFile) sha256(bytes) else null
+        val metadata = hash?.let { mapOf("contentHash" to it) } ?: emptyMap()
+        hash?.let { primeObservation(path, bytes, it) }
         ToolResult.Success(
             invocationId = request.invocationId,
             output = content + note,
@@ -183,6 +194,17 @@ 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

@@ -1,5 +1,6 @@
 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
@@ -193,6 +194,24 @@ 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

@@ -1,5 +1,6 @@
 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
@@ -39,6 +40,9 @@ 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,
@@ -75,6 +79,8 @@ 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.