refactor(events): record tool capabilities on the invocation event

Capability is the canonical signal the plane-2 gates dispatch on, but
ToolInvocationRequestedEvent only carried the tool name — so ReadFilesProjection
classified reads by a hardcoded "file_read" string, bypassing the abstraction and
(worse) re-deriving a semantic fact at replay from whatever the name meant. That
violates the event-sourcing invariant that replay reads recorded facts, not live
state.

Now the tool's requiredCapabilities are recorded on the event at emission, and the
projection classifies by ToolCapability.FILE_READ. To let the lowest module carry
it, ToolCapability moves from core:tools into core:events keeping its package, so
every existing import resolves unchanged and core:tools imports it from below. The
field is defaulted, so pre-existing events deserialize as empty.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/events/src/main/kotlin/com/correx/core/events/events/ToolEvents.kt

@@ -4,6 +4,7 @@ import com.correx.core.approvals.Tier
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.core.events.types.ToolInvocationId
+import com.correx.core.tools.contract.ToolCapability
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
@@ -52,6 +53,10 @@ data class ToolInvocationRequestedEvent(
     val toolName: String,
     val tier: Tier,
     val request: ToolRequest,
+    // The tool's declared capabilities, recorded at emission so replay classifies the call by what
+    // it could actually do (e.g. FILE_READ/FILE_WRITE) without re-deriving from the live registry.
+    // Defaulted for backward compatibility: events written before this field deserialize as empty.
+    val capabilities: Set<ToolCapability> = emptySet(),
 ) : EventPayload
 
 @Serializable

core/events/src/main/kotlin/com/correx/core/tools/contract/ToolCapability.kt

@@ -0,0 +1,21 @@
+package com.correx.core.tools.contract
+
+import kotlinx.serialization.Serializable
+
+/**
+ * What a tool is allowed to do, independent of its name. Plane-2 (`core:toolintent`) rules dispatch
+ * on these — never on tool names — and they are recorded on
+ * [com.correx.core.events.events.ToolInvocationRequestedEvent] at emission, so replay classifies a
+ * call by the capability it actually had rather than re-deriving it from the live registry.
+ *
+ * Lives in `core:events` (the lowest module) so events can carry it; `core:tools` and everything
+ * above import it from here — the package name is unchanged, so the move is import-transparent.
+ */
+@Serializable
+enum class ToolCapability {
+    FILE_READ,
+    FILE_WRITE,
+    NETWORK_ACCESS,
+    SHELL_EXEC,
+    PROCESS_SPAWN,
+}

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

@@ -648,6 +648,7 @@ abstract class SessionOrchestrator(
                     toolName = toolCall.function.name,
                     tier = tier,
                     request = request,
+                    capabilities = tool?.requiredCapabilities ?: emptySet(),
                 ),
             )
             if (toolCall.function.name != STAGE_COMPLETE_TOOL &&

core/toolintent/src/main/kotlin/com/correx/core/toolintent/ReadFilesProjection.kt

@@ -6,6 +6,7 @@ import com.correx.core.events.events.ToolInvocationRequestedEvent
 import com.correx.core.events.types.SessionId
 import com.correx.core.sessions.projections.Projection
 import com.correx.core.toolintent.rules.candidatePathStrings
+import com.correx.core.tools.contract.ToolCapability
 
 /** Reads still awaiting their completion event, plus the paths confirmed read so far. */
 data class ReadFilesState(
@@ -14,11 +15,12 @@ data class ReadFilesState(
 )
 
 /**
- * Folds one session's tool events into the set of file paths it has successfully read. A `file_read`
+ * Folds one session's tool events into the set of file paths it has successfully read. A call counts
- * counts only once its [ToolExecutionCompletedEvent] lands — a read that failed (file not found)
+ * as a read by its recorded [ToolCapability.FILE_READ] capability (not its tool name), and only once
- * never enters the set, so it can't satisfy [com.correx.core.toolintent.rules.ReadBeforeWriteRule].
+ * its [ToolExecutionCompletedEvent] lands — a read that failed (file not found) never enters the
- * Paths are kept as the raw arguments; the rule resolves both sides through the probe, so
+ * set, so it can't satisfy [com.correx.core.toolintent.rules.ReadBeforeWriteRule]. Paths are kept as
- * `./Foo.kt` read and `Foo.kt` written still match. The same projection precedent as
+ * the raw arguments; the rule resolves both sides through the probe, so `./Foo.kt` read and
+ * `Foo.kt` written still match. Same projection precedent as
  * [com.correx.core.sessions.projections.EgressAllowlistProjection].
  */
 class ReadFilesProjection(private val sessionId: SessionId) : Projection<ReadFilesState> {
@@ -33,7 +35,7 @@ class ReadFilesProjection(private val sessionId: SessionId) : Projection<ReadFil
         }
 
     private fun recordPending(state: ReadFilesState, payload: ToolInvocationRequestedEvent): ReadFilesState {
-        if (payload.sessionId != sessionId || payload.toolName != FILE_READ_TOOL) return state
+        if (payload.sessionId != sessionId || ToolCapability.FILE_READ !in payload.capabilities) return state
         val paths = candidatePathStrings(emptyMap(), payload.request.parameters)
         if (paths.isEmpty()) return state
         return state.copy(pending = state.pending + (payload.invocationId.value to paths))
@@ -47,8 +49,4 @@ class ReadFilesProjection(private val sessionId: SessionId) : Projection<ReadFil
             readPaths = state.readPaths + paths,
         )
     }
-
-    private companion object {
-        const val FILE_READ_TOOL = "file_read"
-    }
 }

core/toolintent/src/test/kotlin/com/correx/core/toolintent/ReadFilesProjectionTest.kt

@@ -12,6 +12,7 @@ import com.correx.core.events.types.EventId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.core.events.types.ToolInvocationId
+import com.correx.core.tools.contract.ToolCapability
 import kotlinx.datetime.Instant
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -38,6 +39,7 @@ class ReadFilesProjectionTest {
             toolName = "file_read",
             tier = Tier.T1,
             request = ToolRequest(ToolInvocationId(invId), session, StageId("st"), "file_read", mapOf("path" to path)),
+            capabilities = setOf(ToolCapability.FILE_READ),
         ),
     )
 

core/tools/src/main/kotlin/com/correx/core/tools/contract/ToolCapability.kt

@@ -1,9 +0,0 @@
-package com.correx.core.tools.contract
-
-enum class ToolCapability {
-    FILE_READ,
-    FILE_WRITE,
-    NETWORK_ACCESS,
-    SHELL_EXEC,
-    PROCESS_SPAWN
-}