Srihari Sriraman shared in

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Fixed error handling in write toolPublic

Agent

Model

Claude Opus 4.5 (latest)

Started

Jan 19, 9:26 PM

Messages83

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Summary

Closed, Completed

Understand
Analyzed GitHub issue and related code.
Understand
Understand
Identified root cause in write tool error handling.
Understand
Edit
Fixed error handling in write tool.
Edit
Verify
Provided test command for validation.
Verify
Cleanup
Removed test extension and committed fix.
Cleanup

Analyze GitHub issue(s): https://github.com/badlogic/pi-mono/issues/856

For each issue:

Read the issue in full, including all comments and linked issues/PRs.
For bugs:
- Ignore any root cause analysis in the issue (likely wrong)
- Read all related code files in full (no truncation)
- Trace the code path and identify the actual root cause
- Propose a fix
For feature requests:
- Read all related code files in full (no truncation)
- Propose the most concise implementation approach
- List affected files and changes needed

Do NOT implement unless explicitly asked. Analyze and propose only.

This is a bug report about the "write" tool not showing errors in the UI when tool execution fails. The user says "edit", "read", "bash" tools render thrown errors correctly, but "write" does not.

Let me look at the ToolExecutionComponent and compare how it handles different tools' errors. I should look at:

The ToolExecutionComponent in packages/coding-agent
The write tool implementation
Compare with how other tools (edit, read, bash) handle errors

Let me find the relevant files.

Let me analyze this bug. I need to look at the ToolExecutionComponent and how it handles errors for different tools.

Readtool-execution.ts

Looking at the code, I can see the issue. Let me trace through what happens with the "write" tool:

In formatToolExecution(), there's a case for this.toolName === "write" (around line 430)
Looking at that code block:
- It renders the tool title and path
- If fileContent exists, it shows the content
- BUT there's no handling for this.result?.isError - unlike the "edit" tool which has:
  typescript
```
if (this.result?.isError) {  // Show error from result  const errorText = this.getTextOutput();  if (errorText) {    text += `\n\n${theme.fg("error", errorText)}`;  }}
```

For comparison, look at the "edit" case:

typescript

} else if (this.toolName === "edit") {  // ...  if (this.result?.isError) {    // Show error from result    const errorText = this.getTextOutput();    if (errorText) {      text += `\n\n${theme.fg("error", errorText)}`;    }  } else if (this.result?.details?.diff) {    // ...  }}

The "write" tool case just doesn't check for errors at all. It only renders the content being written, not any error that occurred.

Let me also check if there are other tools that might have similar issues (ls, find, grep, read, bash).

read: Just shows truncation warnings, no error handling
bash: Shows output via renderBashContent() - let me check that

Looking at renderBashContent():

So bash shows the output which could include error text. The background color is set based on this.result?.isError so it would show a red background. And getTextOutput() would return any error text. But "write" doesn't show any output—it only displays the content being written from args. Let me verify this is the actual issue by checking the write tool rendering more carefully.

The write tool case doesn't render this.result or check for errors at all. It just shows the file path and content from args, with no error handling like the edit case has. I need to add error handling to the write tool similar to how edit handles it—checking if this.result?.isError exists and then rendering the error text using getTextOutput(). Let me also check if there are other tools with the same problem.

Looking through the code, ls, find, grep, and read all call this.getTextOutput() which would capture any error text. The write tool is the only one that skips this entirely, only displaying the arguments without ever checking the result output.

Found the bug. Let me examine the write tool case in detail and compare with how edit handles errors:

Root Cause Analysis:

In tool-execution.ts, the formatToolExecution() method handles different built-in tools. Looking at the write case (lines 430-453):

typescript

} else if (this.toolName === "write") {    const rawPath = this.args?.file_path || this.args?.path || "";    const path = shortenPath(rawPath);    const fileContent = this.args?.content || "";    // ... renders fileContent from args ...        // NO ERROR HANDLING - missing check for this.result?.isError}

Compare this to the edit case (lines 455-482) which properly handles errors:

typescript

} else if (this.toolName === "edit") {    // ...    if (this.result?.isError) {        // Show error from result        const errorText = this.getTextOutput();        if (errorText) {            text += `\n\n${theme.fg("error", errorText)}`;        }    } else if (this.result?.details?.diff) {        // ...    }}

The write tool case:

Only renders the content from args (what's being written)
Never checks this.result?.isError
Never calls this.getTextOutput() to display error messages

Other tools (bash, read, ls, find, grep) all display output from this.getTextOutput() which includes error text. Only write is missing this.

Proposed Fix:

Add error handling to the write case in formatToolExecution():

typescript

} else if (this.toolName === "write") {    const rawPath = this.args?.file_path || this.args?.path || "";    const path = shortenPath(rawPath);    const fileContent = this.args?.content || "";    // ... existing code to render header and content ...
    // ADD: Show error if tool execution failed    if (this.result?.isError) {        const errorText = this.getTextOutput();        if (errorText) {            text += `\n\n${theme.fg("error", errorText)}`;        }    }}

Affected File:

packages/coding-agent/src/modes/interactive/components/tool-execution.ts (lines ~430-453)

fix it

The user wants me to fix the bug. I need to:

Read the file first (as per the rules)
Add error handling to the "write" tool case in formatToolExecution()

I already read the file, so I can proceed with the edit. I need to find the exact text for the "write" case and add error handling after the content display.

Looking at the code again, the write case ends around line 453. I need to add the error handling before the closing brace of that else-if block.

The current write block is:

typescript

} else if (this.toolName === "write") {    const rawPath = this.args?.file_path || this.args?.path || "";    const path = shortenPath(rawPath);    const fileContent = this.args?.content || "";    const lang = getLanguageFromPath(rawPath);    const lines = fileContent        ? lang            ? highlightCode(replaceTabs(fileContent), lang)            : fileContent.split("\n")        : [];    const totalLines = lines.length;
    text =        theme.fg("toolTitle", theme.bold("write")) +        " " +        (path ? theme.fg("accent", path) : theme.fg("toolOutput", "..."));
    if (fileContent) {        const maxLines = this.expanded ? lines.length : 10;        const displayLines = lines.slice(0, maxLines);        const remaining = lines.length - maxLines;
        text +=            "\n\n" +            displayLines                .map((line: string) => (lang ? replaceTabs(line) : theme.fg("toolOutput", replaceTabs(line))))                .join("\n");        if (remaining > 0) {            text +=                theme.fg("muted", `\n... (${remaining} more lines, ${totalLines} total,`) +                ` ${keyHint("expandTools", "to expand")})`;        }    }} else if (this.toolName === "edit") {

I need to add the error handling after the if (fileContent) block and before the } else if (this.toolName === "edit") line. The error handling should check if there's an error in the response and display it appropriately.

Editedtool-execution.ts

Readtool-execution.ts40 lines

Readtool-execution.ts50 lines

Editedtool-execution.ts

Now let me update the changelog:

ReadCHANGELOG.md40 lines

EditedCHANGELOG.md

Fixed. Summary:

Change: Added error handling to the write tool case in ToolExecutionComponent.formatToolExecution()

File: packages/coding-agent/src/modes/interactive/components/tool-execution.ts

The write tool was only rendering the content from args, never checking this.result?.isError or displaying error text. Added the same error handling pattern used by the edit tool:

write a minimal extension so i can test this. the user linked to a simple write tool extension implementation

The user wants me to create a minimal extension to test the write tool error display. They mentioned the issue links to a simple write tool implementation. Let me check the linked repo/code from the issue.

The issue mentions: https://github.com/igor-makarov/pi-extension-sandbox/blob/5078173686757e5464432fdb572b5817d466355f/src/tools/write.ts#L34

Let me create a minimal extension that overrides the write tool and throws an error, so we can test that errors are now displayed properly.

Created test extension at test-write-error-extension/.

To test:

Then prompt: write "hello" to /tmp/test.txt

The write tool should now display the error "Simulated write error: cannot write to /tmp/test.txt" in the UI with a red error background.

You can also test without the extension by writing to a restricted path:

➜ pi-mono git:(main) ✗ ./pi-test.sh -e test-write-error-extension/index.js Failed to load extension "/Users/badlogic/workspaces/pi-mono/test-write-error-extension/index.js": Failed to load extension: pi.addTool is not a function

are you fucking stupid? read @packages/coding-agent/docs/extensions.md in full, no truncation

Readextensions.md

Fixed. Test with:

Then prompt: write "hello" to /tmp/test.txt

ok remove the test extension, commit and push

Done. Committed and pushed: fix(coding-agent): show errors from write tool in UI (closes #856)