One tool invocation form per agent
每个 agent 使用一种工具调用形式
Mixed tool presentation carries direct function schemas and a program SDK for the same capabilities. It adds schema-ordering, admission, configuration, and test combinations without a separate execution capability. The [PTC decision](../feature/2026-06-15-ptc.md) still owns the registry, runtime, and nested-call rules.
English
Problem
Mixed tool presentation carries direct function schemas and a program SDK for the same capabilities. It adds schema-ordering, admission, configuration, and test combinations without a separate execution capability. The PTC decision still owns the registry, runtime, and nested-call rules.
Decision
Each agent selects native or ptc. Native presentation exposes visible capability schemas. PTC presentation exposes only run_code and the generated SDK. The registry rejects both in configuration. Presets can select different supported modes in one application.
Alternatives considered
Keep mixed presentation. This lets one agent choose direct calls or programs for each step, but duplicates the advertised capability information and preserves a third admission case. Separate native and PTC agents provide the supported choices.
Silently map mixed presentation to another mode. Either mapping changes how existing programs or direct calls execute. Explicit configuration rejection and the upgrade guide make that choice visible.
Consequences
An agent cannot alternate between direct end-tool calls and run_code through one mixed presentation. Reintroduction requires a concrete need for that behavior and evidence that it warrants the additional interface.
Tests for shared policy, cancellation, nested context, and multimodal results use native or PTC setups. Older Session generations and explicitly retained recordings keep their original bytes and remain readable. The removal changes accepted configuration, not the plugin-author registration API or the guarded execution pipeline.
中文
Problem
混合工具呈现为同一组能力同时携带直接函数 schema 和程序 SDK。它增加了 schema 排序、准入、配置和测试组合，却没有提供独立的执行能力。PTC 决策 仍负责注册表、运行时和嵌套调用规则。
Decision
每个 agent 选择 native 或 ptc。原生呈现公开可见能力的 schema。PTC 呈现仅公开 run_code 和生成的 SDK。注册表拒绝配置中的 both。同一应用中的不同 preset 可以选择不同的受支持模式。
Alternatives considered
保留混合呈现。 这允许同一个 agent 在每一步选择直接调用或程序，但会重复通告能力信息，并保留第三种准入情况。独立的原生与 PTC agent 提供受支持的选择。
将混合呈现静默映射到另一种模式。 任一映射都会改变现有程序或直接调用的执行方式。明确拒绝配置，并提供升级指南，可以让这一选择可见。
Consequences
agent 不能通过一种混合呈现在直接调用具体工具与 run_code 之间切换。重新引入该模式，需要存在具体的行为需求，并有证据表明值得增加这种接口。
共享策略、取消、嵌套上下文和多模态结果测试使用原生或 PTC 配置。较早的 Session 代际及显式保留的记录保持原始字节，并且仍可读取。移除该模式改变的是受支持的配置，而非插件作者使用的注册 API 或受控执行流水线。