feat(tools): let one agent choose its tool presentation, and ship code

Code Mode was a deployment-wide field on the host `tools` row: a
deployment ran every session that way or none. The obvious product
shape — 代码模式 beside 标准/极简/创造 in the preset picker — had
nothing to hang on.

The registry itself cannot move into a preset; the agent loop's
scheduler, the api-proxy's presenters, and every tool plugin are its
consumers. So split the registry from its projection: `presentAs(mode)`
writes one cell on the calling agent's scope layer, exactly as
`restrict()` does, and the three reads that decided presentation take
that scope's mode instead of the service's. The config `mode` becomes
the default agents shadow rather than a process-wide fact.

Two consequences are load-bearing. `run_code` now enters a view only
for scopes whose own mode presents it — a native agent must not find it
dispatchable because another agent in the process does — and the
reserved name holds whatever the configured mode, since any agent may
select a code mode later.

`dsh-agent-tool-mode` is the row a preset carries to declare this. A
code mode waits for the host's `codeRuntime` rather than assuming it,
so a runtime-less deployment fails the preset at mount, naming the
row, instead of at the session's first request.

The shipped `code` preset is `standard` plus that row, ordered second.

docs/config-catalog.md

@@ -225,6 +225,28 @@ Depends on: [`AgentLoopConfig`](#deepseek-aidsh-agent-loop) · [`GoalDomainConfi
 
 Source: [`packages/examples/agent-spine-demo/src/index.ts:90`](../packages/examples/agent-spine-demo/src/index.ts)
 
+## `@deepseek-ai/dsh-agent-tool-mode`
+
+Requires: `tools`
+
+```ts config-catalog
+/** Plugin config. */
+export interface Config {
+  /**
+   * The form this agent's model sees. `native` sends every visible schema,
+   * `code` sends only `run_code` plus a generated SDK, `both` sends both.
+   * Required rather than defaulted: the deployment default is what a profile
+   * without this row already gets, so an omitted value would mean the row was
+   * composed for nothing.
+   */
+  mode: ToolPresentationMode
+}
+```
+
+Depends on: [`ToolPresentationMode`](core-data-structures/tools.md)
+
+Source: [`packages/core/agent-tool-mode/src/index.ts:36`](../packages/core/agent-tool-mode/src/index.ts)
+
 ## `@deepseek-ai/dsh-bash-env`
 
 ```ts config-catalog
@@ -2206,10 +2228,15 @@ Requires: `systemPrompt`
 /** Plugin config: how the registered tools are presented to the model. */
 export interface Config {
   /**
-   * Model presentation. `native` (default) sends every visible schema; `code`
-   * sends only `run_code` plus a generated SDK prompt; `both` sends both forms.
-   * Code modes require a TypeScript runtime and fail prompt assembly when it is
-   * absent or mismatched. Under `code`, native names in `toolOrder` are invalid.
+   * Model presentation for agents that declare none of their own. `native`
+   * (default) sends every visible schema; `code` sends only `run_code` plus a
+   * generated SDK prompt; `both` sends both forms. Code modes require a
+   * TypeScript runtime and fail prompt assembly when it is absent or
+   * mismatched. Under `code`, native names in `toolOrder` are invalid.
+   *
+   * One agent overrides this for itself with {@link ToolRegistry.presentAs},
+   * which is how an agent preset composes a Code Mode agent beside native
+   * ones in the same process.
    */
   mode?: ToolPresentationMode
   /**

docs/cordis-catalog/services.md

@@ -2539,6 +2539,17 @@ Source: [`packages/compact/compact-tool-result-prune/src/index.ts:44`](../../pac
 Tool registry and execution pipeline. Scoped registrations shadow globals; one visibility resolver feeds presentation, lookup, and dispatch.
 
 ```ts cordis-catalog
+/**
+ * Present this agent's tools in `mode` instead of the deployment default.
+ *
+ * Scoped only, and one declaration per agent: this is how an agent preset
+ * composes a Code Mode agent beside native ones in the same process, and a
+ * process-global override would be the `mode` config field instead.
+ * @param mode - the presentation this agent's model sees.
+ * @returns the exact disposer that restores the deployment default.
+ */
+presentAs(mode: ToolPresentationMode): () => void
+
 /**
  * Register globally or in the calling agent scope. Scoped tools shadow
  * globals; duplicates within one layer and the reserved `run_code` name fail.
@@ -2613,9 +2624,9 @@ executionMode(exec: ToolExecutionInput): ToolExecutionMode
 async execute(exec: ToolExecutionInput): Promise<ToolExecutionResult>
 ```
 
-Types: [ScopeKey](../core-data-structures/scope.md) · [ToolDefinition](../core-data-structures/tools.md) · [ToolExecutionInput](../core-data-structures/tools.md) · [ToolExecutionMode](../core-data-structures/tools.md) · [ToolExecutionResult](../core-data-structures/tools.md) · [ToolGuard](../core-data-structures/tools.md) · [ToolRestriction](../core-data-structures/tools.md) · [ToolSchema](../core-data-structures/tools.md)
+Types: [ScopeKey](../core-data-structures/scope.md) · [ToolDefinition](../core-data-structures/tools.md) · [ToolExecutionInput](../core-data-structures/tools.md) · [ToolExecutionMode](../core-data-structures/tools.md) · [ToolExecutionResult](../core-data-structures/tools.md) · [ToolGuard](../core-data-structures/tools.md) · [ToolPresentationMode](../core-data-structures/tools.md) · [ToolRestriction](../core-data-structures/tools.md) · [ToolSchema](../core-data-structures/tools.md)
 
-Source: [`packages/core/tools/src/index.ts:714`](../../packages/core/tools/src/index.ts)
+Source: [`packages/core/tools/src/index.ts:726`](../../packages/core/tools/src/index.ts)
 
 ## `ctx.typert` — `TypertRegistry`