mcp-debugger-usage

# MCP Debugger Usage Use for B2C server-side script debugging. Confirm the sandbox, deployed script, breakpoint, and request before starting a session. ## Prerequisites - Basic Auth for a BM user with `WebDAV_Manage_Customization`: username plus password or WebDAV File Access and UX Studio access key. OAuth is unsupported. - Inspect unknown connection settings with `config_inspect` and the task's `projectDirectory`; keep its default masking. Use resolved values. - Match local source and line numbers to deployed code and the site's cartridge path. A breakpoint's `verified` flag indicates local source mapping, not that matching code is deployed or active. ## Capture and cleanup 1. Call `debug_start_session` with `projectDirectory`. Use `configPath` or `instanceName` only to override the configured selection. Cartridge discovery defaults to that project; use `cartridgeDirectory` only for a different root. Preserve the returned session ID and `resolution`. 2. Call `debug_capture_at_breakpoint` with the file, line, a bounded timeout, and `auto_continue: true` for a snapshot. It arms its own breakpoint; a prior `debug_set_breakpoints` call is unnecessary. Use that tool for separate breakpoint management; it replaces the existing set. 3. Trigger the request. The capture tool's optional trigger supports GET without custom headers; trigger authenticated or non-GET requests externally. An external trigger must run while capture waits, not after awaiting its result. A halted capture can return `trigger_pending: true`; resume with `debug_control` with `action: continue` before expecting that request to finish. Do not retrigger it. 4. Use captured stack, variables, and expressions. For further halted inspection, use `debug_inspect` or `debug_evaluate`. Inspection returns stack and top-frame variables (all scopes) by default; `include` selects stack, variables, or both. Use `frame_index`, `scope`, or `object_path` for targeted inspection. Expressions can have side effects; keep evaluation within the requested scope. 5. Check halted threads with `debug_list_sessions`, resume with `debug_control` with `action: continue`, and always call `debug_end_session` with `clear_breakpoints: true`, including after errors or timeouts. Stop any log watches started for the investigation. ## Stepping After a halt, call `debug_control` with `action: into`, `over`, or `out`, then `debug_wait_for_stop` before inspecting again. `action: continue` runs until the next breakpoint or request completion. End sessions explicitly. ## Recovery - No breakpoint hit: verify deployed code, cartridge path, request, and breakpoint. A timeout leaves the breakpoint armed. Check sessions for a late halt; end with `clear_breakpoints: true` when finished. Do not leave an unbounded capture waiting. - Configuration still unexplained after `config_inspect`: consult [MCP configuration](skill://mcp/b2c-config/SKILL.md). - Missing BM permission/access key: `docs_read({query: "mcp-security"})` for debugger requirements; `guide-authentication` for WebDAV key setup. For other setup issues, `docs_search` with the specific error. If docs tools are unavailable, use [debugger access](https://salesforcecommercecloud.github.io/b2c-developer-tooling/mcp/security#debugger) and [WebDAV key setup](https://salesforcecommercecloud.github.io/b2c-developer-tooling/guide/authentication#webdav-access). General WebDAV OAuth instructions do not apply to the debugger. - Before repeating a failed request, check whether it already changed state. ## CLI or IDE, when requested For terminal debugging use `b2c debug cli`; for a DAP client use `b2c debug`. For those workflows, read [b2c-cli/b2c-debug](skill://b2c-cli/b2c-debug/SKILL.md) when the broader skill collections are enabled, or the [CLI debugger reference](https://salesforcecommercecloud.github.io/b2c-developer-tooling/cli/debug).