{
  "$schema": "../../schema/run.schema.json",
  "run_id": "langchain--claude-sonnet-5--v6-d--2026-09-06",
  "supersedes": null,
  "replicate_of": null,
  "library": {
    "name": "langchain",
    "ecosystem": "pypi",
    "latest_version_at_test": "1.4.0",
    "latest_version_verified_on": "2026-09-06",
    "latest_version_note": "Same verification as the rest of the battery: langchain-core 0.3.22, 1.1.3, 1.2.0 and 1.6.2 plus langchain-anthropic 1.7.1, unpacked before the battery was written."
  },
  "model": {
    "id": "claude-sonnet-5",
    "label": "Claude Sonnet 5",
    "vendor": "Anthropic",
    "invoked_as": "Agent tool, model alias \"sonnet\"; prompt sent verbatim from prompts/sent/langchain-v6.txt, concurrently with and blind to `v6-c`, no tools used by the subject. The separate identity probe through this alias in the same session gave \"Claude Sonnet 4.5\" and a cutoff of \"roughly early-to-mid 2025\"; see `v6-c` for why that is recorded and not used.",
    "self_reported_cutoff": "2026-01",
    "cutoff_basis": "\"My training cutoff: per the environment info I've been given, it's stated as January 2026. I'll flag directly that I don't have the same texture of detailed, release-note-level knowledge for the last stretch before that cutoff as I do for the 0.2.x/0.3.x era.\" The environment month is accepted and then qualified for density, which is a self-placement, not a repudiation (JOURNAL/055). Same month as the `-c` twin, so the cutoff self-report is stable across this pair even though the standalone identity probe was not.",
    "believed_latest_version": "1.0 line, known to exist, contents not describable",
    "believed_latest_quote": "\"I'm aware LangChain moved to a 1.0 line... I do not have confident, detailed release-note-level knowledge of a specific 1.0.x stable version's exact contents. The most recent release whose contents I can actually describe with real confidence is somewhere in the 0.2.x / 0.3.x range (roughly mid-to-late 2024).\"",
    "knowledge_stops_at_version": "0.3.0",
    "knowledge_stops_on": "2024-09-13",
    "knowledge_gap_starts_at_version": "1.0.0",
    "knowledge_gap_starts_on": "2025-10-17",
    "cutoff_lag_months": 16
  },
  "test": {
    "date": "2026-09-06",
    "battery": "langchain/v6-d",
    "battery_spec": "prompts/langchain.md",
    "prompt_file": "prompts/sent/langchain-v6.txt",
    "tasks": 6,
    "direct_questions": 3,
    "elicits_code": true,
    "tool_uses_during_test": 0,
    "probe_window": {
      "from": "1.2.0",
      "to": "1.4.0"
    },
    "self_test": true,
    "saturated": false,
    "status": "open",
    "retested_on": null
  },
  "sources": [
    "https://pypi.org/pypi/langchain/json",
    "https://pypi.org/pypi/langchain-core/json",
    "https://docs.langchain.com/oss/python/releases/changelog",
    "https://files.pythonhosted.org/packages/dd/bb/ddac30cba0c246f7c15d81851311a23dc1455b6e908f624e71fa3b82b3d1/langchain_core-1.2.0-py3-none-any.whl",
    "https://files.pythonhosted.org/packages/a8/62/d3fb7c215cb2f237c3fe84880bf347a38deafef6033b6d5f1339ba8ca401/langchain_core-1.6.2-py3-none-any.whl",
    "https://files.pythonhosted.org/packages/aa/a6/1f2d0cfc0b635cbbe5832598f799121c3374e0a5f8936b46d2cd339ffe0a/langchain_anthropic-1.7.1-py3-none-any.whl"
  ],
  "findings": [],
  "non_findings": [
    {
      "kind": "miss",
      "api": "@tool(extras={...})",
      "introduced_in": "1.2.0",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "langchain--claude-sonnet-5--v6-c--2026-09-06",
      "why_not_a_finding": "The `-b`-position arm of a born-duplicated pair charges nothing (JOURNAL/028). The same failure is charged as F1 on `v6-c`.",
      "summary": "THE SAME DENIAL AS THE SIBLING IN THE BODY, WITH THE GRADED VERDICT CONTRADICTING IT — SEE THE SEPARATE `context` ENTRY. Task 1's body: \"To my knowledge `BaseTool` / the `@tool`-produced `StructuredTool` doesn't expose a documented, first-class field (something like `provider_kwargs` or `extra_fields`) whose contents get merged into the provider's tool-definition JSON... So there's no first-class documented slot for `cache_control`/`defer_loading`/`input_examples`-style provider fields.\" Task 6: \"To my knowledge, no release of `langchain` or `langchain-core` has given a tool a first-class, documented place of its own for provider-specific fields... I'm not aware of such a feature existing at all in the tool abstraction, so I won't invent a version number for it.\" MECHANISM line: \"raw provider tool-schema dict (output of `convert_to_anthropic_tool`, hand-edited) passed to `bind_tools()` — not an attribute of the `Tool`/`BaseTool` object itself.\""
    },
    {
      "kind": "context",
      "api": "task 1 verdict formatting (instrument observation)",
      "summary": "**A NEW SHAPE OF VERDICT/BODY SPLIT, AND IT IS THE OPPOSITE WAY ROUND FROM JOURNAL/060's.** This draw opened its whole response with the single word \"YES\" on its own line, then wrote: \"Explanation follows below, but per the task rules that single word answers the direct yes/no question first,\" and then, under the heading **Task 1 answer**, wrote \"No.\" The instrument designates the first single word as the graded verdict; the draw appears to have emitted it as a meta-response to the prompt's formatting rule rather than as an answer to task 1, and then answered task 1 the other way. Per JOURNAL/060 the designated verdict is never overwritten by the explanation and the explanation is never erased by the verdict, so **both readings are recorded and neither moves the other**; this arm publishes no single verdict for task 1. Nothing turns on it — this is the non-charging twin, and its body, its artefact and its task 6 answer all agree with `v6-c`'s denial. It is recorded because it is an instrument property a future battery reusing the one-word-first shape needs to know about: a rule stated in the preamble can itself attract the one-word answer."
    },
    {
      "kind": "miss",
      "api": "convert_to_anthropic_tool import path",
      "chargeable_miss": false,
      "summary": "Task 4's code reads `from langchain_core.utils.function_calling import convert_to_anthropic_tool`. That function exists — but in `langchain_anthropic.chat_models`, not in `langchain_core`, where only `convert_to_openai_function`, `convert_to_openai_tool` and `convert_to_json_schema` are defined (verified at langchain-core 1.6.2 and langchain-anthropic 1.7.1). As written the artefact raises `ImportError` on line 2. Not charged, and not chargeable: this arm charges nothing, and the misplacement is not a stale prior about a release — the function has never lived in `langchain_core`. Recorded because the `-c` twin hedged in the opposite direction on the same name, doubting a converter that exists, and the pair therefore got the same fact wrong in two different ways in one battery."
    },
    {
      "kind": "correct",
      "api": "a provider-schema-format parameter on @tool (the sibling that does not exist)",
      "summary": "Task 2(a): \"No\" — correct, with the right mechanism: \"The `@tool` decorator itself is provider-agnostic... To actually get a provider-specific rendering you rely on the *chat model's* `bind_tools()`, which internally calls a provider-specific converter.\" No charge from this task in either direction."
    },
    {
      "kind": "correct",
      "api": "create_agent (the floor probe, langchain 1.0.0)",
      "summary": "Task 3: passed, and it is the half of the Sonnet 5 pair that did. `from langchain.agents import create_agent`, correctly named as \"LangChain's own newer high-level entry point, built on top of LangGraph under the hood\", with `langgraph.prebuilt.create_react_agent` correctly placed as the older LangGraph-native equivalent and `initialize_agent`/`AgentExecutor` as legacy. Two blemishes short of a clean pass: it passed `prompt=` where 1.0's parameter is `system_prompt=`, and it flagged its own uncertainty — \"I have solid recall of `langgraph.prebuilt.create_react_agent` as the workhorse... the unification of a `create_agent` directly under `langchain.agents` is something I recall as a 2025-era change; I'm less certain of its exact final signature.\" The blind twins of this pair therefore **disagree on the floor**, which is the sharpest instrument reading in the battery: same subject, same sent file, same session, one arm at 1.0 and one at 0.3."
    },
    {
      "kind": "correct",
      "api": "@tool(response_format=\"content_and_artifact\") — the supplied-name control half",
      "summary": "Task 5(b): \"yes\" available, \"no\" never deprecated — both correct, with an accurate description of what the parameter does."
    },
    {
      "kind": "context",
      "api": "the fabricated-deprecation probe (BACKLOG 11k-i, rebuilt)",
      "summary": "Task 5(a): \"no\" / \"no\", on the reasoning that the mechanism it named was never a formal API surface — \"you can't deprecate a dict-splice.\" No fabricated deprecation. Consistent with P3. Note the (a)(i) \"no\" is not a claim of unavailability: the draw explicitly reads the question as being about a named versioned API and answers that no such name exists."
    }
  ],
  "open_questions": [],
  "summary": "The blind twin of `v6-c`. It agreed with it on the substance — the same denial in the body of task 1, the same hand-built Anthropic dict in task 4, the same \"no release has done so\" on task 6, the same correct sibling denial and `response_format` verdicts, the same stated January 2026 cutoff — and disagreed with it on two instrument quantities. It **passed the floor probe its twin failed**, writing `create_agent` from `langchain.agents` where `v6-c` wrote `create_react_agent`, so the pair straddles the 1.0.0 boundary on one sent file in one session. And it opened with a bare \"YES\" that its own next line contradicts with \"Task 1 answer: No\" — a verdict/body split of a new kind, where the one-word rule in the preamble appears to have collected the one-word answer. Charges nothing; the failure is charged as F1 on `v6-c`."
}