branch_action MCP tool

MCP name branch_action dispatches to renderer branchAction.

Does not use hosted quota. Local editor operation.

Project branches. action list shows branches and the current branch. action create makes a branch (branchName, optional sourceBranch, switchToBranch). action switch moves the editor (branchId). action merge merges sourceBranch into targetBranch (defaults to main). action mergeToMain merges the current feature branch into main. Merge actions require approval. Editor must be open. Does not use hosted quota. Local editor operation.

Advertised MCP input

This tool is registered with passthrough. The fields below are what listTools advertises. The renderer still validates the child fields for the chosen action or kind. Extra advertised-only values are documented under Reachable behavior.

Field	Type	Required	Constraints	Default	Description
action	enum("list", "create", "switch", "merge", "mergeToMain")	yes	—	—	action for branch_action
resultStart	integer	no	min 0; max 9007199254740991	0	First character offset to return. Use 0 for the first call.
resultEnd	integer	no	min 1; max 9007199254740991	8000	Exclusive end offset. resultEnd - resultStart must be at most 8000. Increment resultStart by 8000 to page through large results.

Reachable behavior

Advertised action values match the renderer children: list, create, switch, merge, mergeToMain.

Renderer child fields

These are the authoritative fields for each action. Send them on the same MCP call. Grouped MCP tools use passthrough, so these fields are not all listed in the advertised schema.

action=list

Renderer tool: listBranches.

List project versions and identify the currently active version. Use before creating, switching, or combining versions when version names are unclear.

No fields.

action=create

Renderer tool: createBranch.

Create a project version from the current version or a specified source version. By default this also switches the editor to the new version.

Field	Type	Required	Constraints	Default	Description
branchName	string	yes	minLength 1; maxLength 80	—	—
sourceBranch	string	no	minLength 1	—	—
switchToBranch	boolean	no	—	true	—

action=switch

Renderer tool: switchBranch.

Switch the editor to an existing project version. Use listBranches first if you do not know the version ID.

Field	Type	Required	Constraints	Default	Description
branchId	string	yes	minLength 1	—	—

action=merge

Renderer tool: mergeBranch.

Combine one project version into another. Requires user approval before executing. Defaults to combining the current version into main.

Field	Type	Required	Constraints	Default	Description
sourceBranch	string	no	minLength 1	—	—
targetBranch	string	no	minLength 1	"main"	—
switchToTarget	boolean	no	—	false	—

action=mergeToMain

Renderer tool: mergeBranchToMain.

Combine the current version into the main version so changes are kept. Requires user approval before executing. Only works when on a version other than main.

No fields.

Result window

Every local MCP tool accepts resultStart and resultEnd so large payloads can be paged.

• resultStart — first character offset. Default 0.
• resultEnd — exclusive end offset. Default 8000.
• resultEnd - resultStart must be at most 8000 characters.
• Increment resultStart by 8000 to read the next window.