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Stop Chatting With Spreadsheets — Francesco Galletta & Felippe Felisola Caso, Monzo

111 min videoNov 9, 2026The notes cover it

Build financial AI workflows around explicit assumptions, tested code for calculations, traceable evidence, human decision gates, and independent checks.

  • Interview users until goals, terms, assumptions, and open decisions are explicit; organize work into reviewable steps.
  • Run repeatable calculations in versioned, tested code—not in the model’s arithmetic—and surface test results.
  • Label inputs as facts, estimates, or assumptions; trace outputs to their sources and route consequential choices through human review.

The notes capture the five principles; the workshop UI walkthrough adds some practical detail. · Best for: Teams building AI agents for financial analysis or other high-stakes decisions.

A workshop on designing trustworthy financial-analysis agents. The presenters demonstrate a wedding-budgeting harness and argue that trust comes from the workflow and its controls, not from a single model or prompt.

Trust as the design goal5:14

  • For financial tasks, speed is not the main bottleneck; users need confidence in results.
  • The proposed framework has five principles: shared domain, consistency, evidence, accountability, and verification.

Establish a shared domain and plan20:48

  • Start by explaining the goal, then clarify terms and assumptions through questions rather than jumping straight to implementation.
  • Break the work into decision points; distinguish user-provided facts from model inferences and unresolved questions.
  • Allow corrections and discussion of individual steps without losing the wider plan.

Make calculations consistent36:36

  • Use code for calculations that should give the same result every time, rather than relying on model arithmetic.
  • Test and version the code; surface changes that could affect results and let the harness guide users through building and running tests.

Keep evidence traceable56:20

  • Show where inputs and outputs came from, and how calculations were performed.
  • Distinguish facts, estimates, interpretations, and assumptions; track changes to both source data and code.

Build useful accountability gates1:06:31

  • People remain accountable for agent outputs, so expose meaningful decisions and assumptions instead of treating the agent as a black box.
  • Use a few high-signal review gates for consequential choices, rather than approving every tiny action or reviewing everything line by line.
  • Let users correct inputs and branch into side questions without unintentionally disrupting the main analysis.

Verify with an independent perspective1:20:07

  • Use a separate review or outside reference to challenge assumptions and catch results that seem implausible.
  • Feed material challenges back into the plan; allow reviewers or users to dismiss challenges that do not apply.
  • Choose the harness’s scope based on risk, importance, and how many people will rely on it.

When to build a dedicated harness1:33:23

  • A dedicated harness is most useful when a task needs reproducibility, has meaningful consequences, or repeatedly fails in a general-purpose agent setup.
  • For lower-risk tasks, prompts or skills with human review may be sufficient; avoid building infrastructure that is more work than using it.

Step by step

  1. Describe the financial goal and provide the context you have.
  2. Have the agent ask clarifying questions; resolve ambiguous terms and label facts, estimates, assumptions, and open decisions.
  3. Review the proposed plan as discrete decision points, correct errors, and approve the plan before execution.
  4. Implement repeatable calculations in code, then run unit tests or golden examples and track code versions.
  5. Trace results back to their inputs, sources, assumptions, and calculation code.
  6. Put high-impact decisions behind human review gates and allow corrections without losing unrelated work.
  7. Run an independent check against external references or domain knowledge; incorporate relevant challenges into the plan.

Tools & resources mentioned

  • Workshop repo and UI — example harness and materials for trying the wedding-budget workflow; the transcript mentions a QR code/repo but provides no URL.
  • Build-your-own guide in the repo — instructions for creating a similar harness with the workshop’s principles.
  • Claude and ChatGPT — mentioned as general-purpose assistants, not as the workshop’s core implementation tools.
  • Google Data Studio / Looker Studio — mentioned in the speaker’s career introduction.

Notes are AI-generated from the video's transcript and may miss nuance.