ERD Editor MCP Server: Setup for Claude Code, Codex and Other Apps

• Lists the diagrams the agent can reach

  Shows which ERD documents are open in a connected editor or found on disk.

  Try: “Which ERD diagrams are open?”

  Files · erd_list_documents

• Opens a diagram, or creates a new one

  Opens a document by path. With create set, it makes a missing file and adds .erd.json to a name with no extension.

  Try: “Create a new diagram called shop.”

  Write · erd_open_document

• Lists tables, groups, memos and dictionary rows

  Pages through the diagram's tables by ID, 100 at a time, then groups, memos and dictionary rows, and can find tables by name or comment.

  Try: “Find tables with 'order' in the name.”

  Read · erd_list

• Reads tables or other items by ID or name

  Returns the full details of the tables or entities you name, and lists any it had no room for.

  Try: “Show the users table.”

  Read · erd_get

• Reads the whole diagram as SQL, JSON or a snapshot

  Returns the document as a snapshot, SQL for one of eight databases, JSON or its scripts, or the DDL of just the tables you name. Reads stop at 40,000 characters.

  Try: “Show the PostgreSQL DDL for the orders table.”

  Read · erd_read

• Lists naming problems the dictionaries find

  Reports forbidden words, unknown words, synonyms, duplicate names and type mismatches, with what to use instead.

  Try: “Check my column names against the dictionary.”

  Read · erd_list_checks

• Saves the open diagram

  Saves the diagram when the connected editor, such as VS Code, keeps edits unsaved until saved.

  Try: “Save the diagram.”

  Write · erd_save

• Undoes the agent's last edit

  Reverts the agent's most recent edit, or a whole batch at once, and leaves your own edits alone.

  Try: “Undo that last change.”

  Write · erd_undo

• Redoes an undone edit

  Re-applies an edit that was just undone.

  Try: “Redo it.”

  Write · erd_redo

• Adds a table

  Adds a new table to the diagram.

  Try: “Add a table named customers.”

  Write · erd_add_table

• Removes a table

  Removes a table together with its relationships and indexes.

  Try: “Remove the old_logs table.”

  Delete · erd_remove_table

• Renames a table

  Changes a table's physical name.

  Try: “Rename users to accounts.”

  Write · erd_change_table_name

• Edits a table's comment

  Sets the comment text on a table.

  Try: “Add a comment to orders saying it holds paid orders.”

  Write · erd_change_table_comment

• Sets a table's logical name

  Sets the descriptive name, and derives the physical name from the word dictionary unless you set one by hand.

  Try: “Give the orders table the logical name 'Customer order'.”

  Write · erd_set_table_logical_name

• Changes a table's color

  Sets the color of a table on the canvas.

  Try: “Make the payments table red.”

  Write · erd_change_table_color

• Moves one table on the canvas

  Places a table at new coordinates.

  Try: “Move customers next to orders.”

  Write · erd_move_table

• Moves several tables at once

  Moves a group of tables in one step.

  Try: “Shift the billing tables to the right.”

  Write · erd_move_tables

• Sorts the tables

  Arranges the tables on the canvas automatically.

  Try: “Tidy up the layout.”

  Write · erd_sort_tables

• Adds a column to a table

  Adds a new column to a table with the settings you give.

  Try: “Add an email column to users.”

  Write · erd_add_column

• Removes columns

  Removes one or more columns from a table.

  Try: “Drop the legacy_id column from users.”

  Delete · erd_remove_columns

• Renames a column

  Changes a column's physical name.

  Try: “Rename usr_nm to username.”

  Write · erd_change_column_name

• Changes a column's data type

  Sets the data type of a column, such as varchar(255) or bigint.

  Try: “Make price a decimal(10,2).”

  Write · erd_change_column_data_type

• Sets a column's default value

  Sets the default value of a column.

  Try: “Default status to 'new'.”

  Write · erd_change_column_default

• Edits a column's comment

  Sets the comment on a column.

  Try: “Comment that total is in cents.”

  Write · erd_change_column_comment

• Sets a column's logical name

  Sets the descriptive name and derives the physical name and domain from the dictionaries, unless you set one by hand.

  Try: “Give email the logical name 'Email address'.”

  Write · erd_set_column_logical_name

• Links a column to a domain

  Applies a dictionary domain to a column.

  Try: “Use the Email domain for the email column.”

  Write · erd_set_column_domain

• Marks a column as primary key

  Turns the primary key flag on or off for a column.

  Try: “Make id the primary key.”

  Write · erd_set_column_primary_key

• Marks a column as unique

  Turns the unique flag on or off for a column.

  Try: “Make email unique.”

  Write · erd_set_column_unique

• Marks a column as not null

  Turns the not null flag on or off for a column.

  Try: “Make name required.”

  Write · erd_set_column_not_null

• Marks a column as auto increment

  Turns auto increment on or off for a column.

  Try: “Auto-increment the id column.”

  Write · erd_set_column_auto_increment

• Moves a column within a table

  Changes the order of a column in its table.

  Try: “Put created_at last.”

  Write · erd_move_column

• Adds a relationship between tables

  Creates a foreign-key style link from one table to another.

  Try: “Link orders to customers.”

  Write · erd_add_relationship

• Links two columns in a relationship

  Connects a specific column on one side to a column on the other side.

  Try: “Link orders.customer_id to customers.id.”

  Write · erd_link_columns

• Removes a relationship

  Deletes a relationship between two tables.

  Try: “Remove the link between logs and users.”

  Delete · erd_remove_relationship

• Changes a relationship's type

  Switches a relationship between kinds such as one-to-one and one-to-many.

  Try: “Make that link one-to-one.”

  Write · erd_change_relationship_type

• Sets what a delete does to related rows

  Sets the ON DELETE action of a relationship, such as cascade.

  Try: “Set ON DELETE CASCADE on orders to customers.”

  Write · erd_change_relationship_on_delete

• Sets what an update does to related rows

  Sets the ON UPDATE action of a relationship.

  Try: “Set ON UPDATE RESTRICT on that link.”

  Write · erd_change_relationship_on_update

• Adds an index

  Adds an index to a table.

  Try: “Add an index on orders.created_at.”

  Write · erd_add_index

• Removes an index

  Deletes an index from a table.

  Try: “Remove the old name index.”

  Delete · erd_remove_index

• Renames an index

  Changes an index's name.

  Try: “Rename idx1 to idx_orders_date.”

  Write · erd_change_index_name

• Makes an index unique or not

  Turns the unique setting of an index on or off.

  Try: “Make that index unique.”

  Write · erd_set_index_unique

• Adds a column to an index

  Adds another column to an existing index.

  Try: “Add status to that index.”

  Write · erd_add_index_column

• Removes a column from an index

  Takes a column out of an index.

  Try: “Take status out of that index.”

  Delete · erd_remove_index_column

• Reorders columns in an index

  Changes the position of a column inside an index.

  Try: “Put created_at first in the index.”

  Write · erd_move_index_column

• Sets ascending or descending for an index column

  Sets the sort order of one column in an index.

  Try: “Sort created_at descending in the index.”

  Write · erd_set_index_column_order

• Adds a sticky note

  Adds a memo to the canvas.

  Try: “Add a note explaining the billing tables.”

  Write · erd_add_memo

• Removes a sticky note

  Deletes a memo from the canvas.

  Try: “Remove the TODO note.”

  Delete · erd_remove_memo

• Edits a sticky note

  Changes the text of a memo.

  Try: “Update the note to say v2.”

  Write · erd_change_memo_value

• Recolors a sticky note

  Changes a memo's color.

  Try: “Make the note yellow.”

  Write · erd_change_memo_color

• Moves a sticky note

  Places a memo at new coordinates.

  Try: “Move the note beside payments.”

  Write · erd_move_memo

• Resizes a sticky note

  Changes a memo's width and height.

  Try: “Make the note wider.”

  Write · erd_resize_memo

• Adds a table group

  Adds a labeled box that can hold tables.

  Try: “Add a group called Billing.”

  Write · erd_add_table_group

• Removes a table group

  Deletes a group box.

  Try: “Remove the Billing group.”

  Delete · erd_remove_table_group

• Renames a table group

  Changes a group's name.

  Try: “Rename Billing to Payments.”

  Write · erd_change_table_group_name

• Recolors a table group

  Changes a group's color.

  Try: “Make the group blue.”

  Write · erd_change_table_group_color

• Moves a table group

  Places a group at new coordinates.

  Try: “Move the group down.”

  Write · erd_move_table_group

• Resizes a table group

  Changes a group's width and height.

  Try: “Enlarge the group.”

  Write · erd_resize_table_group

• Puts tables into a group

  Assigns tables to a table group.

  Try: “Put orders and payments in the Billing group.”

  Write · erd_set_table_group

• Adds a dictionary word

  Adds a word to the naming dictionary.

  Try: “Add the word 'customer' with the abbreviation 'cust'.”

  Write · erd_add_word

• Edits a dictionary word

  Changes an existing dictionary word.

  Try: “Change the abbreviation for 'customer'.”

  Write · erd_update_word

• Removes a dictionary word

  Deletes a word from the naming dictionary.

  Try: “Remove the word 'temp'.”

  Delete · erd_remove_word

• Adds a dictionary term

  Adds a term to the dictionary.

  Try: “Add the term 'Email address'.”

  Write · erd_add_term

• Edits a dictionary term

  Changes a term in the dictionary.

  Try: “Fix the type of the Email term.”

  Write · erd_update_term

• Removes a dictionary term

  Deletes a term from the dictionary.

  Try: “Remove the unused term.”

  Delete · erd_remove_term

• Adds a domain

  Adds a reusable data type definition to the dictionary.

  Try: “Add a domain for money values.”

  Write · erd_add_domain

• Edits a domain

  Changes a domain's type or settings.

  Try: “Make the money domain decimal(12,2).”

  Write · erd_update_domain

• Removes a domain

  Deletes a domain from the dictionary.

  Try: “Remove the unused domain.”

  Delete · erd_remove_domain

• Re-derives physical names from the dictionaries

  Recomputes physical names for a column, a table or the whole document after a word or term changed.

  Try: “Re-derive all physical names.”

  Write · erd_derive_physical_names

• Sets the target database

  Chooses which database the diagram's SQL is written for.

  Try: “Switch the diagram to MySQL.”

  Write · erd_set_database

• Sets the database name

  Changes the name of the database in the diagram.

  Try: “Name the database shop.”

  Write · erd_set_database_name

• Edits the schema SQL scripts

  Sets the scripts that go before or after the generated DDL.

  Try: “Add a CREATE EXTENSION line at the top.”

  Write · erd_set_ddl_script

• Imports SQL into the diagram

  Loads a SQL dump and builds tables from it. It replaces the diagram unless mode is append.

  Try: “Import this schema.sql into the diagram.”

  Write · erd_import_sql

• Imports a GraphQL schema

  Builds tables from a GraphQL schema. It replaces the diagram unless mode is append.

  Try: “Import this GraphQL schema.”

  Write · erd_import_graphql

• Imports DBML

  Builds tables from DBML. It replaces the diagram unless mode is append.

  Try: “Import this DBML file.”

  Write · erd_import_dbml

• Imports AML

  Builds tables from AML text. It replaces the diagram unless mode is append.

  Try: “Import this AML.”

  Write · erd_import_aml

• Imports a diagram from JSON

  Loads a full diagram from JSON, replacing the current one unless mode is append.

  Try: “Load this exported JSON.”

  Write · erd_import_json

• Runs up to 100 edits as one step

  Applies up to 100 edits in order, all or none, and one undo reverts the batch. Later steps can use IDs created earlier.

  Try: “Create an orders table with five columns in one go.”

  Write · erd_batch

Watch out for

• It can remove tables and columns from your diagram file

  Tools such as erd_remove_table, erd_remove_columns and the import tools delete or replace parts of the diagram. erd_undo reverts the agent's own edits, so keep the file in git. npmjs.com

• The imports replace the whole diagram by default

  The SQL, GraphQL, DBML, AML and JSON imports replace the current diagram unless you ask for append mode. Say 'append' in your prompt if you want to keep what is there. npmjs.com

• Without an editor it writes straight to the file

  When no editor holds the diagram, edits are written to the .erd.json file on disk. Open the diagram in your editor to see changes live. npmjs.com

• Edits in a closed JetBrains IDE can be overwritten

  The README says a JetBrains IDE does not reload an open diagram, so close it there before the agent edits the file. Obsidian prefers the agent's edit over an unsaved one. npmjs.com

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