Edit tool fails with "old_string does not appear in file" due to fileContentCache never being populated

[0bserver07]

When using claude-code-acp with an ACP client that implements readTextFile, the Edit tool fails
with:
Error: The provided old_string does not appear in the file: "..."

Even when the file clearly contains the text. (I tried .html but also .txt)

Reproduction steps:

1. Connect an ACP client that implements readTextFile and writeTextFile
2. Ask Claude to edit a file (e.g., "change the title in index.html from X to Y")
3. Claude reads the file successfully
4. Claude attempts to edit → fails with the above error

Root cause:
Two issues:

Root cause #1 - Caching condition never true:

• https://github.com/zed-industries/claude-code-acp/blob/main/src/acp-agent.ts#L624 - The condition
  !params.limit && !params.line is never satisfied
• https://github.com/zed-industries/claude-code-acp/blob/main/src/mcp-server.ts#L106-L111 - Read
  tool defaults that cause the issue:
  offset: z.number().optional().default(1),
  limit: z.number().optional().default(defaults.linesToRead),

Root cause #2 - Unhandled exception:

• https://github.com/zed-industries/claude-code-acp/blob/main/src/acp-agent.ts#L662-L666 - First
  unhandled toolInfoFromToolUse() call
• https://github.com/zed-industries/claude-code-acp/blob/main/src/acp-agent.ts#L729-L733 - Second
  unhandled toolInfoFromToolUse() call

Where the actual error is thrown:

• https://github.com/zed-industries/claude-code-acp/blob/main/src/mcp-server.ts#L671 -
  replaceAndCalculateLocation throws when old_string not found
• https://github.com/zed-industries/claude-code-acp/blob/main/src/tools.ts#L113-L114 - Uses
  cachedFileContent[path] || "" (empty string when not cached)

Fix branch: https://github.com/0bserver07/claude-code-acp/tree/fix/edit-tool-cache-bug

[benbrandt]

thanks for reporting! I will take a look