Part 14 · Module 2: The Protocol and Its Transports

Topic 6: Module 2 milestone and interview questions

9 min read·22 Sept 2026

Project Milestone

After this module your working copy of notes-assistant contains the Module 1 files plus these new examples:

text

notes-assistant/
  examples/
    m02_server.py            the Module 2 prototype server (stdio and Streamable HTTP)
    m02_wire.py              raw stdio JSON-RPC driver, no SDK
    m02_wiretap.py           records every stdio line between a client and a server
    m02_raw_stdio.py         discover, call, progress, cancellation on the raw wire
    m02_errors.py            the error catalogue over stdio
    m02_curl_errors.sh       HTTP-only errors (-32700, -32600, -32020, 405)
    m02_curl_legacy.sh       the initialize handshake and Mcp-Session-Id by hand
    m02_legacy_vs_modern.py  the SDK Client in auto and legacy mode, through the wiretap
    m02_handles.py           a reading-list handle used across connections
    m02_paged_server.py      a low-level server with cursor pagination
    m02_pagination.py        the cursor loop, and -32602 versus -32603 for bad cursors
    m02_utilities.py         progress, cancellation, ping, completions, resource links
    m02_noisy_server.py      a server with stray print() calls (the failure case)
    m02_noisy_demo.py        what a polluted stdout looks like to two clients
    m02_env_demo.py          credentials reach stdio servers only through env
    m02_curl.sh              Streamable HTTP by hand: JSON and SSE responses
    m02_start_http.sh        starts the HTTP server on port 8020 (logs in http.log)
    m02_json_mode.sh         the same progress call against json_response=True
    m02_http_cancel.sh       cancellation by closing the HTTP stream
    m02_stdout_check.sh      the empty-stdin check for a polluted stdout
    m02_security.sh          Origin and Host checks against DNS rebinding
    m02_bind_demo.sh         the 0.0.0.0 pitfall and the allowlist fix
    m02_old_sse_server.py    the deprecated HTTP+SSE transport, for comparison
    m02_old_sse_demo.sh      its two-connection flow by hand
    m02_latency.py           in-memory versus stdio versus HTTP timings
    m02_bytes.sh             bytes on the wire, modern versus legacy
    m02_lab.py               the Module Lab

Code explained

In simple words: the file map of the project after Module 2.
What happens: every file above is a script you ran in this module. None of them change notes_assistant/; the prototype server imports NoteStore from it, as Module 1's did. The scripts write only wire.log, stdout.txt, http.log, and server.pid in the project root, which you can delete.
Comes out: the design has moved one step closer to the canonical server of Module 5: search_notes, notes://{note_id}, notes://index, and summarise_topic exist with their final names, logs go to stderr, and the HTTP entry point binds to 127.0.0.1 by default. Still missing are create_note, input validation with Field constraints, annotations, configuration through Settings, and tests; Modules 3 to 5 add them. The reading-list tools and reindex_notes are teaching props for this module and do not carry forward.

Project Milestone

The rest of this course is yours to keep