# M01-L03 — Sources, tools, and uncertainty

**Outcome:** Separate a grounded claim, a proposed tool action, and an observed result.

**Start:** M01-L02 and its saved context comparison.

A source supports a claim only when it actually contains the relevant information and applies to the exact object under discussion. A part family name, search snippet, or plausible citation is insufficient for a consequential board decision. Open the primary document, identify the variant and revision, and inspect the relevant sentence or table. Keep the claim and supporting location together.

Retrieval can bring additional material into context, while tools can read files or execute commands. Neither guarantees that the final interpretation is correct. A command shown in chat is a proposal; a tool result is an observation with an execution context. A compiler result supports a build claim for the source and options used. It does not establish physical operation. [OpenAI tool use](https://developers.openai.com/api/docs/guides/tools)

Work through this original sample answer: “The fixture is invalid, so BenchNote outputs FAULT. Three successful readings clear the fault. Run the tests; they will pass.” The first claim is supported by the Chapter 2 passage. The second invents a recovery count. The final sentence proposes an action and predicts its result; it is not an executed test.

Revise it to preserve the supported rule, state that recovery is unspecified, and name a concrete check without claiming execution. This is a useful engineering answer even though it contains an unknown. It points to the missing requirement and avoids making the test report say more than occurred.

In your notebook, use separate fields for documented, inferred, tested, and unresolved. A hypothesis can be useful without being called a root cause. Record what observation would distinguish it from another explanation. This habit becomes central to debugging later.

![The current request, selected history, relevant references, and actual tool results enter bounded context. The generated answer still needs verification.](../../../../book/figures/D03.png)

*D03. The current request, selected history, relevant references, and actual tool results enter bounded context. The generated answer still needs verification.*

## Practice and completion

Complete the [exercise](exercise.md), then compare your artifact with the separately distributed instructor answer. A lesson acknowledgment records your own progress; it does not certify that a physical test occurred.

## Reading and figures

[Chapter 2](../../../../book/chapters/ch02/chapter.md). Resources: [Original BenchNote note](../../../../book/chapters/ch02/resources/benchnote-note.md) and [original reference responses](../../../../book/chapters/ch02/resources/reference-responses.md). Figure references: SS02-02–03; D03.