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Custom DAP Extensions

Dapper extends the standard Debug Adapter Protocol with custom events and requests. This page documents all non-standard messages so that clients and tools integrating with Dapper know what to expect.

All custom message types use the dapper/ namespace prefix to avoid collisions with any future DAP standard additions.

Custom Events

dapper/childProcess

Emitted when a child process is detected and automatically attached (requires autoAttachChildProcesses: true in the launch configuration).

Body fields:

Field Type Description
pid int Process ID of the child process.
parentPid int Process ID of the parent that spawned it.
command string Command line used to start the child process.
ipcEndpoint string IPC endpoint address the child's adapter is listening on.

dapper/processStarted

Emitted when a debugged child process has started and the adapter has successfully connected to it.

Body fields:

Field Type Description
pid int Process ID of the newly started process.
ipcEndpoint string IPC endpoint for this process's adapter connection.

dapper/processExited

Emitted when a debugged child process has exited.

Body fields:

Field Type Description
pid int Process ID of the exited process.
exitCode int Exit code returned by the process.

Custom Requests

Dapper currently documents only the custom requests and events that are considered stable enough for external consumers. Additional request types may be added here as they are finalized.

Capability Flags

Dapper advertises non-standard capabilities in the initialize response body alongside the standard DAP capability flags.

Flag Type Description
supportsChildProcessDebugging bool true when the adapter can automatically attach to child processes spawned by the debugged program. Clients should show the autoAttachChildProcesses option in their UI when this is true.

Capability flags that are experimental, internal, or still evolving are intentionally omitted from this page until their external contract is stable.

See Also