hasura/graphql-engine · error · CommandsError::DuplicateCommandArgumentDefinition

the following argument in command {command_name:} is defined

Error message

the following argument in command {command_name:} is defined more than once: {argument_name:}

What it means

DuplicateCommandArgumentDefinition is raised when a single command declares the same argument name twice. Argument names must be unique within a command because they map to named GraphQL/input fields.

Source

Thrown at v3/crates/metadata-resolve/src/stages/commands/error.rs:72

            _other => None,
        }
    }
}

#[derive(Debug, thiserror::Error)]
pub enum CommandsError {
    #[error("the following command is defined more than once: {name:}")]
    DuplicateCommandDefinition { name: Qualified<CommandName> },
    #[error(
        "the argument '{argument_name}' in command '{command_name}' has an unknown type: {argument_type}"
    )]
    UnknownCommandArgumentType {
        command_name: Qualified<CommandName>,
        argument_name: Spanned<ArgumentName>,
        argument_type: TypeReference,
    },
    #[error(
        "the following argument in command {command_name:} is defined more than once: {argument_name:}"
    )]
    DuplicateCommandArgumentDefinition {
        command_name: Qualified<CommandName>,
        argument_name: Spanned<ArgumentName>,
    },
    #[error("source for the following command is defined more than once: {command_name:}")]
    DuplicateCommandSourceDefinition {
        command_name: Qualified<CommandName>,
    },
    #[error(
        "the source data connector {data_connector:} for command {command_name:} has not been defined"
    )]
    UnknownCommandDataConnector {
        command_name: Qualified<CommandName>,
        data_connector: Qualified<DataConnectorName>,
    },
    #[error(

View on GitHub (pinned to 724551b9ae)

Solutions

1. Find the duplicated argument_name in the command's arguments and remove/rename one occurrence
2. If generating metadata programmatically, de-duplicate by argument name before writing
3. Check YAML merge keys/anchors are not reintroducing an argument that is also defined inline

Example fix

# before
arguments:
  limit:
    type: Int
  limit:            # duplicate
    type: Int

# after
arguments:
  limit:
    type: Int
  offset:
    type: Int

fn assert_unique_arguments(cmd: &Command) -> Result<(), String> {
    let mut seen = HashSet::new();
    for name in cmd.arguments.keys() {
        if !seen.insert(name.clone()) {
            return Err(format!("command {} has duplicate argument {name}", cmd.name));
        }
    }
    Ok(())
}

Match DuplicateCommandArgumentDefinition and report command_name + argument_name (the Spanned argument carries source position for precise highlighting).

When it happens

Trigger: Listing an argument name twice in one command's arguments mapping — often via YAML anchors, defaults merging, or copy-paste within the same command's arguments block.

Common situations: Copy-pasting argument blocks and forgetting to rename; YAML merge keys (<<:) accidentally including a key already defined explicitly; programmatic metadata generation emitting an argument twice.

Related errors

• the following command is defined more than once: {name:}
• source for the following command is defined more than once:
• error in getting server feature flags %w
• parsing 'admin_secrets' from config.yaml / environment varia
• the relationship '{relationship_name}' is defined more than

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/f5415a54f9261621. Report an issue: GitHub.