# 工具使用后挂钩

onPostToolUse 钩子会在工具成功执行后被调用。 使用它可执行以下操作：

<!-- markdownlint-disable GHD046 GHD005 -->

<!-- Suppressed: GHD046 (outdated release terminology), GHD005 (hardcoded data variable) -->

* 转换或筛选工具结果
* 记录工具执行以用于审计
* 基于结果添加上下文
* 隐藏对话的结果

> ```
>           **失败变体** — `onPostToolUse` 仅会在工具成功执行时触发。 若要查看**失败的**工具调用，请注册`onPostToolUseFailure`（在 Python 中为`on_post_tool_use_failure`，在 Go/.NET 中为`OnPostToolUseFailure`，在 Rust 中为`on_post_tool_use_failure`）。 处理程序接收 `{ sessionId, toolName, toolArgs, error, timestamp, workingDirectory }` - `error` 字段是从工具的失败结果中提取的字符串， 并可能返回 `{ additionalContext: string }` 为模型注入额外的指导（例如重试提示）。 有关完整列表，请参阅 [AUTOTITLE](/copilot/how-tos/copilot-sdk/hooks/hooks-overview) 。
> ```

<a id="failure-variant"></a>

## 挂钩签名

<div class="ghd-codetabs">
<div class="ghd-codetab" data-lang="typescript" data-label="TypeScript"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">TypeScript</div>

```typescript
import type {
  PostToolUseHookInput,
  HookInvocation,
  PostToolUseHookOutput,
} from "@github/copilot-sdk";
type PostToolUseHandler = (
  input: PostToolUseHookInput,
  invocation: HookInvocation,
) => Promise<PostToolUseHookOutput | null | undefined>;
```

```typescript
type PostToolUseHandler = (
  input: PostToolUseHookInput,
  invocation: HookInvocation,
) => Promise<PostToolUseHookOutput | null | undefined>;
```

</div>

<div class="ghd-codetab" data-lang="python" data-label="Python"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">Python</div>

```python
from copilot.session import PostToolUseHookInput, PostToolUseHookOutput
from typing import Callable, Awaitable

PostToolUseHandler = Callable[
    [PostToolUseHookInput, dict[str, str]],
    Awaitable[PostToolUseHookOutput | None]
]
```

```python
PostToolUseHandler = Callable[
    [PostToolUseHookInput, dict[str, str]],
    Awaitable[PostToolUseHookOutput | None]
]
```

</div>

<div class="ghd-codetab" data-lang="go" data-label="Go"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">Go</div>

```golang
package main

import copilot "github.com/github/copilot-sdk/go"

type PostToolUseHandler func(
    input copilot.PostToolUseHookInput,
    invocation copilot.HookInvocation,
) (*copilot.PostToolUseHookOutput, error)

func main() {}
```

```golang
type PostToolUseHandler func(
    input PostToolUseHookInput,
    invocation HookInvocation,
) (*PostToolUseHookOutput, error)
```

</div>

<div class="ghd-codetab" data-lang="dotnet" data-label=".NET"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">.NET</div>

```csharp
using GitHub.Copilot;

public delegate Task<PostToolUseHookOutput?> PostToolUseHandler(
    PostToolUseHookInput input,
    HookInvocation invocation);
```

```csharp
public delegate Task<PostToolUseHookOutput?> PostToolUseHandler(
    PostToolUseHookInput input,
    HookInvocation invocation);
```

</div>

<div class="ghd-codetab" data-lang="java" data-label="Java"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">Java</div>

```java
import com.github.copilot.rpc.*;
import java.util.concurrent.CompletableFuture;

public class PostToolUseSignature {
    PostToolUseHandler handler = (PostToolUseHookInput input, HookInvocation invocation) ->
        CompletableFuture.completedFuture(null);
    public static void main(String[] args) {}
}
```

```java
@FunctionalInterface
public interface PostToolUseHandler {
    CompletableFuture<PostToolUseHookOutput> handle(
        PostToolUseHookInput input,
        HookInvocation invocation);
}
```

</div>

</div>

## 输入

| 领域                 | 类型        | Description |
| ------------------ | --------- | ----------- |
| `timestamp`        | SDK 时间戳类型 | 触发钩子时       |
| `workingDirectory` | 字符串       | 当前工作目录      |
| `toolName`         | 字符串       | 已调用的工具的名称   |
| `toolArgs`         | 对象        | 传递给工具的参数    |
| `toolResult`       | 对象        | 工具返回的结果     |

## 输出

返回 `null` 或 `undefined` 传递结果不变。 否则，返回包含以下任何字段的对象：

| 领域                  | 类型      | Description          |
| ------------------- | ------- | -------------------- |
| `modifiedResult`    | 对象      | 要使用的修改结果，而不是原始结果     |
| `additionalContext` | 字符串     | 向对话注入额外上下文           |
| `suppressOutput`    | boolean | 如果为 true，则结果不会显示在对话中 |

## 示例

### 记录所有工具结果

<div class="ghd-codetabs">
<div class="ghd-codetab" data-lang="typescript" data-label="TypeScript"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">TypeScript</div>

```typescript
const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input, invocation) => {
      console.log(`[${invocation.sessionId}] Tool: ${input.toolName}`);
      console.log(`  Args: ${JSON.stringify(input.toolArgs)}`);
      console.log(`  Result: ${JSON.stringify(input.toolResult)}`);
      return null; // Pass through unchanged
    },
  },
});
```

</div>

<div class="ghd-codetab" data-lang="python" data-label="Python"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">Python</div>

```python
from copilot.session import PermissionHandler

async def on_post_tool_use(input_data, invocation):
    print(f"[{invocation['session_id']}] Tool: {input_data['toolName']}")
    print(f"  Args: {input_data['toolArgs']}")
    print(f"  Result: {input_data['toolResult']}")
    return None  # Pass through unchanged

session = await client.create_session(on_permission_request=PermissionHandler.approve_all, hooks={"on_post_tool_use": on_post_tool_use})
```

</div>

<div class="ghd-codetab" data-lang="go" data-label="Go"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">Go</div>

```golang
package main

import (
    "context"
    "fmt"
    copilot "github.com/github/copilot-sdk/go"
)

func main() {
    client := copilot.NewClient(nil)
    session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
        OnPermissionRequest: copilot.PermissionHandler.ApproveAll,
        Hooks: &copilot.SessionHooks{
            OnPostToolUse: func(input copilot.PostToolUseHookInput, inv copilot.HookInvocation) (*copilot.PostToolUseHookOutput, error) {
                fmt.Printf("[%s] Tool: %s\n", inv.SessionID, input.ToolName)
                fmt.Printf("  Args: %v\n", input.ToolArgs)
                fmt.Printf("  Result: %v\n", input.ToolResult)
                return nil, nil
            },
        },
    })
    _ = session
}
```

```golang
session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
    Hooks: &copilot.SessionHooks{
        OnPostToolUse: func(input copilot.PostToolUseHookInput, inv copilot.HookInvocation) (*copilot.PostToolUseHookOutput, error) {
            fmt.Printf("[%s] Tool: %s\n", inv.SessionID, input.ToolName)
            fmt.Printf("  Args: %v\n", input.ToolArgs)
            fmt.Printf("  Result: %v\n", input.ToolResult)
            return nil, nil
        },
    },
})
```

</div>

<div class="ghd-codetab" data-lang="dotnet" data-label=".NET"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">.NET</div>

```csharp
using GitHub.Copilot;

public static class PostToolUseExample
{
    public static async Task Main()
    {
        await using var client = new CopilotClient();
        var session = await client.CreateSessionAsync(new SessionConfig
        {
            Hooks = new SessionHooks
            {
                OnPostToolUse = (input, invocation) =>
                {
                    Console.WriteLine($"[{invocation.SessionId}] Tool: {input.ToolName}");
                    Console.WriteLine($"  Args: {input.ToolArgs}");
                    Console.WriteLine($"  Result: {input.ToolResult}");
                    return Task.FromResult<PostToolUseHookOutput?>(null);
                },
            },
        });
    }
}
```

```csharp
var session = await client.CreateSessionAsync(new SessionConfig
{
    Hooks = new SessionHooks
    {
        OnPostToolUse = (input, invocation) =>
        {
            Console.WriteLine($"[{invocation.SessionId}] Tool: {input.ToolName}");
            Console.WriteLine($"  Args: {input.ToolArgs}");
            Console.WriteLine($"  Result: {input.ToolResult}");
            return Task.FromResult<PostToolUseHookOutput?>(null);
        },
    },
});
```

</div>

<div class="ghd-codetab" data-lang="java" data-label="Java"><div class="ghd-codetab-fallback-label" role="heading" aria-level="3">Java</div>

<!-- docs-validate: skip -->

```java
import com.github.copilot.*;
import com.github.copilot.rpc.*;
import java.util.concurrent.CompletableFuture;

var hooks = new SessionHooks()
    .setOnPostToolUse((input, invocation) -> {
        System.out.println("[" + invocation.getSessionId() + "] Tool: " + input.getToolName());
        System.out.println("  Args: " + input.getToolArgs());
        System.out.println("  Result: " + input.getToolResult());
        return CompletableFuture.completedFuture(null);
    });

var session = client.createSession(
    new SessionConfig()
        .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
        .setHooks(hooks)
).get();
```

</div>

</div>

### 对敏感数据进行修订

```typescript
const SENSITIVE_PATTERNS = [
  /api[_-]?key["\s:=]+["']?[\w-]+["']?/gi,
  /password["\s:=]+["']?[\w-]+["']?/gi,
  /secret["\s:=]+["']?[\w-]+["']?/gi,
];

const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input) => {
      if (typeof input.toolResult === "string") {
        let redacted = input.toolResult;
        for (const pattern of SENSITIVE_PATTERNS) {
          redacted = redacted.replace(pattern, "[REDACTED]");
        }

        if (redacted !== input.toolResult) {
          return { modifiedResult: redacted };
        }
      }
      return null;
    },
  },
});
```

### 截断大型结果

```typescript
const MAX_RESULT_LENGTH = 10000;

const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input) => {
      const resultStr = JSON.stringify(input.toolResult);

      if (resultStr.length > MAX_RESULT_LENGTH) {
        return {
          modifiedResult: {
            truncated: true,
            originalLength: resultStr.length,
            content: resultStr.substring(0, MAX_RESULT_LENGTH) + "...",
          },
          additionalContext: `Note: Result was truncated from ${resultStr.length} to ${MAX_RESULT_LENGTH} characters.`,
        };
      }
      return null;
    },
  },
});
```

### 基于结果添加上下文

```typescript
const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input) => {
      // If a file read returned an error, add helpful context
      if (input.toolName === "read_file" && input.toolResult?.error) {
        return {
          additionalContext:
            "Tip: If the file doesn't exist, consider creating it or checking the path.",
        };
      }

      // If shell command failed, add debugging hint
      if (input.toolName === "shell" && input.toolResult?.exitCode !== 0) {
        return {
          additionalContext:
            "The command failed. Check if required dependencies are installed.",
        };
      }

      return null;
    },
  },
});
```

### 筛选错误堆栈跟踪

```typescript
const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input) => {
      if (input.toolResult?.error && input.toolResult?.stack) {
        // Remove internal stack trace details
        return {
          modifiedResult: {
            error: input.toolResult.error,
            // Keep only first 3 lines of stack
            stack: input.toolResult.stack.split("\n").slice(0, 3).join("\n"),
          },
        };
      }
      return null;
    },
  },
});
```

### 合规性审核线索

```typescript
interface AuditEntry {
  timestamp: Date;
  sessionId: string;
  toolName: string;
  args: unknown;
  result: unknown;
  success: boolean;
}

const auditLog: AuditEntry[] = [];

const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input, invocation) => {
      auditLog.push({
        timestamp: input.timestamp,
        sessionId: invocation.sessionId,
        toolName: input.toolName,
        args: input.toolArgs,
        result: input.toolResult,
        success: !input.toolResult?.error,
      });

      // Optionally persist to database/file
      await saveAuditLog(auditLog);

      return null;
    },
  },
});
```

### 抑制嘈杂结果

```typescript
const NOISY_TOOLS = ["list_directory", "search_codebase"];

const session = await client.createSession({
  hooks: {
    onPostToolUse: async (input) => {
      if (NOISY_TOOLS.includes(input.toolName)) {
        // Summarize instead of showing full result
        const items = Array.isArray(input.toolResult)
          ? input.toolResult
          : input.toolResult?.items || [];

        return {
          modifiedResult: {
            summary: `Found ${items.length} items`,
            firstFew: items.slice(0, 5),
          },
        };
      }
      return null;
    },
  },
});
```

## 最佳做法

1. **无需更改时返回 `null`** - 这比返回空对象或相同的结果更有效。

2. **谨慎修改结果** - 更改结果可能会影响模型对工具输出的解释方式。 仅在必要时进行修改。

3. **使用 `additionalContext` 提供提示** - 不要修改结果，而是添加上下文以帮助模型理解这些结果。

4. **日志记录时考虑隐私** - 工具结果可能包含敏感数据。 在记录前应用编辑。

5. ```
             **保持钩子快速** - 后置工具钩子会同步运行。 应该以异步或批量的方式进行繁重的处理。
   ```

## 另见

* [使用挂钩](/zh/copilot/how-tos/copilot-sdk/hooks)
* [工具使用前挂钩](/zh/copilot/how-tos/copilot-sdk/hooks/pre-tool-use)
* [错误处理挂钩](/zh/copilot/how-tos/copilot-sdk/hooks/error-handling)