Fit every model request to its context window

Every turn re-sent the whole transcript with nothing checking it against
the model's window. On a local model that fails silently: Ollama drops
the start of an over-long prompt, which is where the system prompt and
the plan are. Measured on the Jetson's llama3.2, cut at 4096 tokens with
no error.

- The model catalog reads max_input_tokens and max_output_tokens from
  LiteLLM's model_info, and startup refuses a role on a model with no
  declared window
- BudgetedClient wraps both routes. It fits the canonical events before
  rendering: older tool results cut to head and tail, then the oldest
  turns dropped with a note, keeping calls with their results; a request
  that still cannot fit fails with ContextOverflow and is never sent.
  The output ceiling is the smaller of config and the model's limit
- Tokens are estimated from characters, pessimistically, and the
  estimate is corrected from reported prompt sizes, only ever upward
- The executor takes its scope from the log: the latest plan, which is
  the approved milestone plan, goes in its system prompt, and it sees
  only events after it
- Tool output keeps its head and, mostly, its tail, so a test runner's
  failure summary survives truncation
- tuning.context.keep_recent_turns and safety_margin are new knobs
- scripts/probe_context.py checks a declared window against what the
  server does; it confirmed llama3.2 cuts at the declared 4096
- The tuning guide covers the budget, declaring a local model's limits,
  and the probe

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

nisse-dev/tests/test_agent_build.py

@@ -26,6 +26,8 @@ TEST_CATALOG = ModelCatalog.from_payload(
                 "model_info": {
                     "litellm_provider": "anthropic",
                     "supports_function_calling": True,
+                    "max_input_tokens": 200000,
+                    "max_output_tokens": 64000,
                 },
             }
             for alias in ("claude-opus-5", "claude-haiku-4-5")
@@ -185,8 +187,8 @@ def test_delegation_uses_the_passthrough_route(
 
     agent = build_offline(tmp_path, origin, monkeypatch)
     delegation = agent.orchestrator._delegate
-    assert isinstance(delegation._client, AnthropicPassthroughClient)
-    assert isinstance(agent.orchestrator._executor._client, LiteLLMClient)
+    assert isinstance(delegation._client._inner, AnthropicPassthroughClient)
+    assert isinstance(agent.orchestrator._executor._client._inner, LiteLLMClient)
     agent.stop()
 
 
@@ -194,8 +196,8 @@ def test_httpx_clients_are_not_shared_between_routes(
     tmp_path: Path, origin: Path, monkeypatch
 ) -> None:
     agent = build_offline(tmp_path, origin, monkeypatch)
-    normalized = agent.orchestrator._executor._client._http
-    passthrough = agent.orchestrator._delegate._client._http
+    normalized = agent.orchestrator._executor._client._inner._http
+    passthrough = agent.orchestrator._delegate._client._inner._http
     assert isinstance(normalized, httpx.Client)
     assert normalized is not passthrough  # different base URLs and headers
     agent.stop()
@@ -244,6 +246,7 @@ def test_a_tool_less_model_warns_but_still_boots(tmp_path: Path, monkeypatch) ->
                     "model_info": {
                         "litellm_provider": "openai",
                         "supports_function_calling": False,
+                        "max_input_tokens": 32768,
                     },
                 }
                 for alias in ("claude-opus-5", "claude-haiku-4-5")
@@ -338,6 +341,7 @@ def test_tuning_reaches_every_component(
     assert delegation._caps.wall_clock_s == 60
     assert executor._workspace._timeout_s == 300
     assert executor._workspace._max_output_chars == 2000
-    assert executor._client._max_tokens == 8192
-    assert delegation._client._max_tokens == 8192
+    assert executor._client._inner._max_tokens == 8192
+    assert delegation._client._inner._max_tokens == 8192
+    assert executor._client._max_output_tokens == 8192
     agent.stop()