Foldkit DevTools MCP Server: Setup for Claude, Cursor and Other Apps

• Reads the app's current state

  Returns the current Model, or just a part of it by path. Large values are summarized to fit.

  Try: “Show me the cart part of the current Model.”

  Read · foldkit_get_model

• Reads the app's state at a past step

  Returns the Model as it was after a given history entry. Entries older than the rolling buffer are rejected.

  Try: “What did the Model look like just before message 42?”

  Read · foldkit_get_model_at

• Shows how the app started

  Returns the first Model, the Commands from init, and the Mounts that fired on first render, with their arguments.

  Try: “What did the app do on startup?”

  Read · foldkit_get_init

• Lists the messages the app handled

  Pages through history with each message body, the Commands and Mounts it triggered, and what changed in the Model. You can filter by changed paths or read the latest entries.

  Try: “List the last 20 messages that changed the user part of the Model.”

  Read · foldkit_list_messages

• Counts messages by type

  Counts history entries by message tag, highest first, without their payloads. A quick way to spot noisy messages.

  Try: “Which messages fire most often?”

  Read · foldkit_count_messages_by_tag

• Compares the state at two steps

  Shows path-by-path what changed between the Models at two history indices.

  Try: “What changed between step 10 and step 25?”

  Read · foldkit_diff_models

• Reads one history entry

  Returns one entry by index. To see the Model around it, read the Model at the index before and after.

  Try: “Show message 17 in full.”

  Read · foldkit_get_message

• Lists steps you can jump back to

  Returns the history indices Foldkit can replay to. Index -1 is the initial Model.

  Try: “Which points can I replay to?”

  Read · foldkit_list_keyframes

• Rewinds the app to an earlier step

  Time-travels the running app to a past state and pauses it there until you resume. It changes what the open browser tab shows.

  Try: “Rewind the app to the state before the error.”

  Write · foldkit_replay_to_keyframe

• Resumes the app after a rewind

  Lets the app run normally again after a replay.

  Try: “Resume the app.”

  Write · foldkit_resume

• Sends a message into the running app

  Dispatches one Message as if the app produced it. The app checks it against your Schema and returns an error when it does not match.

  Try: “Send the AddItem message with item id 5.”

  Write · foldkit_dispatch_message

• Sends up to 100 messages in order

  Dispatches a batch of 1 to 100 Messages. All are validated first, so one bad entry rejects the whole batch and nothing is sent.

  Try: “Run these three messages in order and show the new state.”

  Write · foldkit_dispatch_messages

• Used by the assistant behind the scenes

  Lists open Foldkit app tabs

  Shows every browser tab running a Foldkit app that is connected, with its project folder. The assistant calls it first to pick which app to inspect.

  Try: “Which Foldkit apps are connected right now?”

  Read · foldkit_list_runtimes

• Shows history range and pause status

  Reports how much history is kept, whether the app is paused or live, and whether init is recorded.

  Try: “Is the app paused, and how far back can I look?”

  Read · foldkit_get_runtime_state

• Shows which messages the app accepts

  Describes the app's Message Schema, from a short list of variants down to the exact shape of one, so valid messages can be built without reading the code.

  Try: “What messages can I send to this app?”

  Read · foldkit_get_message_schema

Watch out for

• It can read everything your app holds

  An agent can read current and past Models, every message payload and Command arguments. Keep API keys, tokens and personal data out of those values. github.com

• It can send messages and rewind the app

  Dispatch tools make the app act as if a user did something, and replay pauses it. Leave the Message schema out of the DevTools config if you only want reading. github.com

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