Prompt is too long error from Claude Code

[ejstembler]

Summary

The new Claude Code integration mostly works well. After a while I get a "Prompt is too long" response and I cannot continue. Even if my message is small. I'm guessing it accumulates the prompt until it's too big? I can start a new session, but then it forgets everything and I have to explain it all again.

Description

Steps to trigger the problem:

1. Start a new Claude Code agent session
2. Use it for a while
3. Eventualy encounter "Prompt is too long" response

Expected Behavior: It works
Actual Behavior: It eventually stops working

Model Provider Details

• Provider: Claude Code
• Mode: Agent Panel
• Other Details (MCPs, other settings, etc): N/A

Zed Version and System Specs

Zed: v0.202.5 (Zed)
OS: macOS 15.6.1
Memory: 64 GiB
Architecture: x86_64

[imprakharshukla]

Happens with me as soon as I start a thread. A 'hey!' triggers "prompt too long".

[tibeer]

If you e.g. use lm-studio and enable debugging, you can see that zed adds a whole bunch of additional context. Here is a simple hi:

Log

2025-09-05 13:14:13 [DEBUG]
 Received request: POST to /api/v0/chat/completions with body  {
  "model": "qwen/qwen3-4b-2507",
  "messages": [
    {
      "role": "system",
      "content": "You are a highly skilled software engineer with ex... <Truncated in logs> ...\nOperating System: macos\nDefault Shell: /bin/zsh\n\n"
    },
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "hi"
        },
        {
          "type": "text",
          "text": "hi"
        },
        {
          "type": "text",
          "text": "hi"
        }
      ]
    }
  ],
  "stream": true,
  "max_tokens": -1,
  "stop": [],
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "copy_path",
        "description": "Copies a file or directory in the project, and ret... <Truncated in logs> ...d over that approach whenever copying is the goal.",
        "parameters": {
          "required": [
            "source_path",
            "destination_path"
          ],
          "properties": {
            "source_path": {
              "description": "The source path of the file or directory to copy.\n... <Truncated in logs> ...ce_path of \"directory1/a/something.txt\"\n</example>",
              "type": "string"
            },
            "destination_path": {
              "description": "The destination path where the file or directory s... <Truncated in logs> ...ination_path of \"directory2/b/copy.txt\"\n</example>",
              "type": "string"
            }
          },
          "description": "Copies a file or directory in the project, and ret... <Truncated in logs> ...d over that approach whenever copying is the goal.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "create_directory",
        "description": "Creates a new directory at the specified path with... <Truncated in logs> ...need to create new directories within the project.",
        "parameters": {
          "required": [
            "path"
          ],
          "properties": {
            "path": {
              "description": "The path of the new directory.\n\n<example>\nIf the p... <Truncated in logs> ...ng a path of \"directory1/new_directory\"\n</example>",
              "type": "string"
            }
          },
          "description": "Creates a new directory at the specified path with... <Truncated in logs> ...need to create new directories within the project.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "delete_path",
        "description": "Deletes the file or directory (and the directory's... <Truncated in logs> ...project, and returns confirmation of the deletion.",
        "parameters": {
          "required": [
            "path"
          ],
          "properties": {
            "path": {
              "description": "The path of the file or directory to delete.\n\n<exa... <Truncated in logs> ... a path of \"directory1/a/something.txt\"\n</example>",
              "type": "string"
            }
          },
          "description": "Deletes the file or directory (and the directory's... <Truncated in logs> ...project, and returns confirmation of the deletion.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "diagnostics",
        "description": "Get errors and warnings for the project or a speci... <Truncated in logs> ...error. The user can help you fix it.\n</guidelines>",
        "parameters": {
          "properties": {
            "path": {
              "description": "The path to get diagnostics for. If not provided, ... <Truncated in logs> ... should use the path `ipsum/dolor.txt`.\n</example>",
              "type": [
                "string",
                "null"
              ]
            }
          },
          "type": "object",
          "description": "Get errors and warnings for the project or a speci... <Truncated in logs> ...error. The user can help you fix it.\n</guidelines>",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "edit_file",
        "description": "This is a tool for creating a new file or editing ... <Truncated in logs> ...arent directory exists and is the correct location",
        "parameters": {
          "definitions": {
            "EditFileMode": {
              "type": "string",
              "enum": [
                "edit",
                "create",
                "overwrite"
              ]
            }
          },
          "required": [
            "display_description",
            "path",
            "mode"
          ],
          "description": "This is a tool for creating a new file or editing ... <Truncated in logs> ...arent directory exists and is the correct location",
          "type": "object",
          "properties": {
            "display_description": {
              "description": "A one-line, user-friendly markdown description of ... <Truncated in logs> ...nput object so that we can display it immediately.",
              "type": "string"
            },
            "path": {
              "description": "The full path of the file to create or modify in t... <Truncated in logs> ...\n</example>\n\n<example>\n`frontend/db.js`\n</example>",
              "type": "string"
            },
            "mode": {
              "description": "The mode of operation on the file. Possible values... <Truncated in logs> ...iting it as opposed to recreating it from scratch.",
              "allOf": [
                {
                  "$ref": "#/definitions/EditFileMode"
                }
              ]
            }
          },
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "fetch",
        "description": "Fetches a URL and returns the content as Markdown.",
        "parameters": {
          "required": [
            "url"
          ],
          "properties": {
            "url": {
              "description": "The URL to fetch.",
              "type": "string"
            }
          },
          "description": "Fetches a URL and returns the content as Markdown.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "find_path",
        "description": "Fast file path pattern matching tool that works wi... <Truncated in logs> ...al 'offset' parameter to request subsequent pages.",
        "parameters": {
          "required": [
            "glob"
          ],
          "properties": {
            "glob": {
              "description": "The glob to match against every path in the projec... <Truncated in logs> ...hs by providing a glob of \"*thing*.txt\"\n</example>",
              "type": "string"
            },
            "offset": {
              "description": "Optional starting position for paginated results (0-based).\nWhen not provided, starts from the beginning.",
              "type": "integer",
              "format": "uint",
              "minimum": 0,
              "default": 0
            }
          },
          "description": "Fast file path pattern matching tool that works wi... <Truncated in logs> ...al 'offset' parameter to request subsequent pages.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "grep",
        "description": "Searches the contents of files in the project with... <Truncated in logs> ...olely to escape characters in the tool parameters.",
        "parameters": {
          "required": [
            "regex"
          ],
          "properties": {
            "regex": {
              "description": "A regex pattern to search for in the entire projec... <Truncated in logs> ...will only be matched against the code **content**.",
              "type": "string"
            },
            "include_pattern": {
              "description": "A glob pattern for the paths of files to include i... <Truncated in logs> ...mitted, all files in the project will be searched.",
              "type": [
                "string",
                "null"
              ]
            },
            "offset": {
              "description": "Optional starting position for paginated results (0-based).\nWhen not provided, starts from the beginning.",
              "type": "integer",
              "format": "uint32",
              "minimum": 0,
              "default": 0
            },
            "case_sensitive": {
              "description": "Whether the regex is case-sensitive. Defaults to false (case-insensitive).",
              "type": "boolean",
              "default": false
            }
          },
          "description": "Searches the contents of files in the project with... <Truncated in logs> ...olely to escape characters in the tool parameters.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "list_directory",
        "description": "Lists files and directories in a given path. Prefer the `grep` or `find_path` tools when searching the codebase.",
        "parameters": {
          "required": [
            "path"
          ],
          "properties": {
            "path": {
              "description": "The fully-qualified path of the directory to list ... <Truncated in logs> ...az`, you should use the path `foo/baz`.\n</example>",
              "type": "string"
            }
          },
          "description": "Lists files and directories in a given path. Prefer the `grep` or `find_path` tools when searching the codebase.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "move_path",
        "description": "Moves or rename a file or directory in the project... <Truncated in logs> ...or directory without changing its contents at all.",
        "parameters": {
          "required": [
            "source_path",
            "destination_path"
          ],
          "properties": {
            "source_path": {
              "description": "The source path of the file or directory to move/r... <Truncated in logs> ...ce_path of \"directory1/a/something.txt\"\n</example>",
              "type": "string"
            },
            "destination_path": {
              "description": "The destination path where the file or directory s... <Truncated in logs> ...tion_path of \"directory2/b/renamed.txt\"\n</example>",
              "type": "string"
            }
          },
          "description": "Moves or rename a file or directory in the project... <Truncated in logs> ...or directory without changing its contents at all.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "now",
        "description": "Returns the current datetime in RFC 3339 format.\nO... <Truncated in logs> ...k would benefit from knowing the current datetime.",
        "parameters": {
          "definitions": {
            "Timezone": {
              "oneOf": [
                {
                  "description": "Use UTC for the datetime.",
                  "type": "string",
                  "const": "utc"
                },
                {
                  "description": "Use local time for the datetime.",
                  "type": "string",
                  "const": "local"
                }
              ]
            }
          },
          "required": [
            "timezone"
          ],
          "description": "Returns the current datetime in RFC 3339 format.\nO... <Truncated in logs> ...k would benefit from knowing the current datetime.",
          "type": "object",
          "properties": {
            "timezone": {
              "description": "The timezone to use for the datetime.",
              "allOf": [
                {
                  "$ref": "#/definitions/Timezone"
                }
              ]
            }
          },
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "read_file",
        "description": "Reads the content of the given file in the project... <Truncated in logs> ...read a path that hasn't been previously mentioned.",
        "parameters": {
          "required": [
            "path"
          ],
          "properties": {
            "path": {
              "description": "The relative path of the file to read.\n\nThis path ... <Truncated in logs> ...uld use the path `directory2/file.txt`.\n</example>",
              "type": "string"
            },
            "start_line": {
              "description": "Optional line number to start reading on (1-based index)",
              "type": [
                "integer",
                "null"
              ],
              "format": "uint32",
              "minimum": 0,
              "default": null
            },
            "end_line": {
              "description": "Optional line number to end reading on (1-based index, inclusive)",
              "type": [
                "integer",
                "null"
              ],
              "format": "uint32",
              "minimum": 0,
              "default": null
            }
          },
          "description": "Reads the content of the given file in the project... <Truncated in logs> ...read a path that hasn't been previously mentioned.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "terminal",
        "description": "Executes a shell one-liner and returns the combine... <Truncated in logs> ...can't rely on any state from previous invocations.",
        "parameters": {
          "required": [
            "command",
            "cd"
          ],
          "properties": {
            "command": {
              "description": "The one-liner command to execute.",
              "type": "string"
            },
            "cd": {
              "description": "Working directory for the command. This must be one of the root directories of the project.",
              "type": "string"
            }
          },
          "description": "Executes a shell one-liner and returns the combine... <Truncated in logs> ...can't rely on any state from previous invocations.",
          "type": "object",
          "additionalProperties": false
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "thinking",
        "description": "A tool for thinking through problems, brainstormin... <Truncated in logs> ...egies, or outline approaches before taking action.",
        "parameters": {
          "required": [
            "content"
          ],
          "properties": {
            "content": {
              "description": "Content to think about. This should be a description of what to think about or a problem to solve.",
              "type": "string"
            }
          },
          "description": "A tool for thinking through problems, brainstormin... <Truncated in logs> ...egies, or outline approaches before taking action.",
          "type": "object",
          "additionalProperties": false
        }
      }
    }
  ]
}

I also have not figured out yet, where I can change this behaviour or even disable it.

[rterbush]

I've run into this as well and was actually throttled today while using the claude agent. First time in a few weeks and had only worked for a few hours. This must be the reason for that.

[mattheworiordan]

Similar issue for me, my conversation/session is effectively terminated at this point is there is no means to compact the context. Significant blocker to using this in anger.

[mackgorski]

Same happens for me even on prompt that are very short! e.g.:

Proceed to next step toward 90% test coverage and all green tests. Don't forget integration tests with auth-service microservice since user-service heavily depends on it.
Great work on SLO targets/definitions. Ensure full documentation in @README.md covering:

- How to run all tests
- SLO visualization methods and alert setup

Issue: @README.md line 405 references non-existent documents. Create these after completing test and architecture work.

All I get is exactly the response of doom Prompt is too long which is HUGE BS as Claude Code in my Warp terminal handles way longer prompts than this easily! How to remove this constraint as with this this ACP with Claude Code in Zed is useless...

[dglav]

I cannot even start from scratch by creating a new thread. Well, I guess I'm back to using the terminal for claude code.

Some suggested features:

• compact automatically
• user triggered compact
• reset context in new thread

[katie-z-geer]

Hey all:

• Compaction is not supported over the Claude Code SDK. We relayed this to Anthropic, but it's unclear when it will be supported.
• We agree this is a big issue, unfortunately, it's primarily out of our hands.
• Some people mentioned that they would get "prompt too long" immediately, I think this is because they included big files in the prompt.
• We should improve how big files are included in the context, both for @-mentions, and read tool calls. In our native agent, we send an outline of the file when its too big.
• If you'd like, please open/bump issues in https://github.com/anthropics/claude-code about SDK limitations

[ejstembler]

Hey all:

• Compaction is not supported over the Claude Code SDK. We relayed this to Anthropic, but it's unclear when it will be supported.
• We agree this is a big issue, unfortunately, it's primarily out of our hands.
• Some people mentioned that they would get "prompt too long" immediately, I think this is because they included big files in the prompt.
• We should improve how big files are included in the context, both for @-mentions, and read tool calls. In our native agent, we send an outline of the file when its too big.
• If you'd like, please open/bump issues in https://github.com/anthropics/claude-code about SDK limitations

Just to clarify, when I run claude in a terminal window, this error never shows up. So it likely does exist somewhere with your integration or their SDK...