refactor: simplify canonical tool result seams

Review cleanups: dead imports, contentFrom happy-path flattening, codemodeTool shadow rename, call-site param naming for toModelOutput/toMetadata, spec Context fields matching the code, progress-metadata leniency comment, and PLAN.md marked implemented.

packages/core/src/tool/PLAN.md

@@ -2,9 +2,9 @@
 
 ## Status
 
-This document describes the agreed target design for V2 tools. It is an implementation plan, not documentation for the current API.
+Implemented on this branch. This document is the historical plan kept for reviewer context; the authoritative semantic overview is [`specs/v2/tools.md`](../../../../specs/v2/tools.md), and where the two disagree the spec and code win. Delete this file at merge.
 
-The current semantic overview remains in [`specs/v2/tools.md`](../../../../specs/v2/tools.md) until this plan is implemented. The plan's base is `origin/v2` at `b91dd78ab3`. Progress-event ephemerality already landed there (`5a9ed4d350`, `fix: make tool progress live-only`), including the failed-event partial snapshot this plan builds on. Delta-compressed progress is a later follow-up.
+The plan's base was `origin/v2` at `b91dd78ab3`. Progress-event ephemerality already landed there (`5a9ed4d350`, `fix: make tool progress live-only`), including the failed-event partial snapshot this plan builds on. Delta-compressed progress is a later follow-up.
 
 ## Reader And Job
 

packages/core/src/tool/glob.ts

@@ -8,7 +8,7 @@ import { FileSystem } from "../filesystem"
 import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "../location"
 import { Ripgrep } from "../ripgrep"
-import { NonNegativeInt, RelativePath } from "../schema"
+import { RelativePath } from "../schema"
 import { PermissionV2 } from "../permission"
 import { Tool } from "./tool"
 

packages/core/src/tool/grep.ts

@@ -9,7 +9,7 @@ import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "../location"
 import { PermissionV2 } from "../permission"
 import { Ripgrep } from "../ripgrep"
-import { NonNegativeInt, RelativePath } from "../schema"
+import { RelativePath } from "../schema"
 import { Tool } from "./tool"
 
 export const name = "grep"

packages/plugin/src/v2/effect/tool.ts

@@ -95,15 +95,12 @@ export type Definition<Input extends SchemaType<any>, Output extends SchemaType<
    * Optional model projection. Receives the typed domain output. When absent, an
    * encoded string becomes text and any other encoded JSON is serialized once.
    */
-  readonly toModelOutput?: (input: {
+  readonly toModelOutput?: (call: {
     readonly input: InputValue<Input>
     readonly output: OutputValue<Output>
   }) => ModelOutput
   /** Optional compact UI metadata. Receives the typed domain output. Absent means absent: no defaults. */
-  readonly toMetadata?: (input: {
-    readonly input: InputValue<Input>
-    readonly output: OutputValue<Output>
-  }) => Metadata
+  readonly toMetadata?: (call: { readonly input: InputValue<Input>; readonly output: OutputValue<Output> }) => Metadata
 }
 
 /** A dynamic tool's split result: a machine value for Code Mode and content for the model. */

packages/schema/src/session-event.ts

@@ -414,6 +414,9 @@ export namespace Tool {
     type: "session.tool.progress",
     schema: {
       ...ToolBase,
+      // Deliberately looser than terminal metadata (JSON-only): live snapshots
+      // are ephemeral, and only the JSON-validated subset survives into a
+      // durable failure snapshot.
       metadata: Schema.Record(Schema.String, Schema.Unknown),
       content: Schema.Array(ToolContent),
     },

specs/v2/tools.md

@@ -34,14 +34,13 @@ Every local tool receives the same concrete invocation context:
 interface Tool.Context {
   readonly sessionID: Session.ID
   readonly agent: Agent.ID
-  readonly assistantMessageID: SessionMessage.ID
-  readonly toolCallID: string
+  readonly messageID: SessionMessage.ID
+  readonly callID: string
+  readonly progress: (update: Progress) => Effect.Effect<void>
 }
 ```
 
-`assistantMessageID` is the durable ID of the assistant message containing the call. The Session runner owns this association and supplies the complete context to the registry; the registry does not infer it.
-
-Durable events call the invocation identifier `callID`; `Tool.Context.toolCallID` is the same value at the executor boundary.
+`messageID` is the durable ID of the assistant message containing the call. The Session runner owns this association and supplies the complete context to the registry; the registry does not infer it. `callID` carries the same invocation identifier durable events use.
 
 Decoded tool input is passed separately to `execute`. Raw provider input and domain services do not belong in the invocation context.
 
@@ -105,8 +104,8 @@ yield *
             agent: context.agent,
             source: {
               type: "tool",
-              messageID: context.assistantMessageID,
-              callID: context.toolCallID,
+              messageID: context.messageID,
+              callID: context.callID,
             },
             action: "grep",
             resources: [input.pattern],
@@ -160,7 +159,7 @@ Outcomes remain distinct:
 - `ToolFailure` is an expected model-visible failure.
 - Interruption cancels the invocation and is not a tool result.
 - Unexpected typed errors and defects follow the runner's operational failure policy.
-- Unknown and invalid calls become explicit model-visible settlement errors without invoking a handler.
+- Unknown and invalid calls become explicit model-visible execution errors without invoking a handler.
 
 Leaf tools translate only errors they deliberately classify as recoverable. Broad cause-catching around an executor is invalid because it consumes interruption and defects.