tai/taicpp/docs/llm.md

llm: providers, ChatClient, JSON, Python semantics

Port of tai.py 6957-8650 (backends, ModelHealth, ChatClient) plus the helpers they need. Namespace detz::llm (detz::py for Python semantics, detz::json for JSON). The old placeholder API (openai/anthropic providers) is removed: tai.py has no such providers.

File	tai.py origin
json.cpp	json.dumps/loads/raw_decode byte-exact (ensure_ascii, separators, float repr, JSONDecodeError text, big ints)
py.cpp	code-point len/slice, strip/lower/upper/split, str/repr/int/float, datetime (_fromisoformat, fold-aware naive local), sha1/sha256, utf8_replace
helpers.cpp	BackendError, truncate, estimate_tokens, clean_history, tool_args_*, action_signature, conversation_tokens
model_health.cpp	ModelHealth, reward and weight functions
models.cpp	split_models, parse_backends, fetch_model_ids, fetch_pollinations_free, is_free_*, prefer_muse, openrouter_free_tier
cli_backends.cpp	opencode/grok/claude/codex/gemini prompts, parsers, runners, health, probe_backend, opencode_headers
muse.cpp	muse session map, flock+thread locks, muse_run streaming runner
chat_client.cpp	ChatClient (candidates, ordering, pins, retry rounds, single shot, streaming, update_models, models_report)
http_transport.cpp	libcurl transport with an injectable fake (set_transport)
proc.cpp	subprocess.run/Popen, shutil.which
ports.h	LlmConfig, LogSink, BoxPort
unicode_data.cpp (generated)	case maps, whitespace, digits from Python

--update-models is agent::update_models_command(config).

Gaps: see docs/agent.md. Unit tests never touch the network; the libcurl transport itself is only exercised by compile/link, not against a live server.