diff --git a/documentation/INDEX.md b/documentation/INDEX.md
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--- a/documentation/INDEX.md
+++ b/documentation/INDEX.md
@@ -76,6 +76,7 @@ This repository documents the **Durable** component (durable execution orchestra
 | WA003 | GitHub epics, tasks, and project tracking | [wa/WA003-github-epics-tasks-and-project-tracking.md](wa/WA003-github-epics-tasks-and-project-tracking.md) |
 | WA004 | MIT license for the repository and Composer packages | [wa/WA004-mit-license-distribution.md](wa/WA004-mit-license-distribution.md) |
 | WA005 | The canvas is the source, `layouts/index.html` is output | [wa/WA005-the-canvas-is-the-source-the-page-is-output.md](wa/WA005-the-canvas-is-the-source-the-page-is-output.md) |
+| WA006 | English is the working language; French documentation is a product | [wa/WA006-english-is-the-working-language.md](wa/WA006-english-is-the-working-language.md) |
 
 ## Opportunity solution trees (OST)
 
diff --git a/documentation/wa/WA006-english-is-the-working-language.md b/documentation/wa/WA006-english-is-the-working-language.md
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@@ -0,0 +1,101 @@
+# WA006 — English is the working language; French documentation is a product
+
+## Status
+
+Accepted — 4 September 2026. Widens [WA001](WA001-english-language-documentation.md), which stays in force.
+
+## Context
+
+WA001 settled the language of `documentation/`, `.cursor/rules/` and the ADRs. It said nothing about
+everything else the project writes, and the gap filled itself with French: pull request titles and
+bodies, issue and review comments, commit messages, prise files, journal entries.
+
+That was tenable while the repository was read by one person. It stopped being tenable the moment
+the work became public. **A contributor who lands on a pull request cannot review a change whose
+justification they cannot read** — and the justification is the part that matters here, because this
+project routinely writes down *why* a fix takes the shape it takes. On 3 September 2026 a
+cross-review of the seven open pull requests produced findings whose value was entirely in their
+argument; every one of those arguments was in French.
+
+There is also a second, quieter cost. The repository already contains English documentation that
+cites French artefacts — an `UPGRADE.md` note pointing at a French pull request, an ADR referencing a
+French journal entry. A reader following those links leaves the language they were reading in,
+mid-sentence.
+
+## Agreement
+
+**English is the working language of this project.** It applies to everything the project writes,
+whether it lives in the repository or on GitHub:
+
+| Surface | Language |
+|---|---|
+| Pull request titles and bodies | English |
+| Issue titles and bodies | English |
+| Comments — on issues, on pull requests, inline review comments | English |
+| Review summaries and approvals | English |
+| Commit messages, including trailers | English |
+| Prise files under `.worktrees/prises/` | English |
+| Journal entries under `documentation/journal/` | English (already required by WA001) |
+| ADRs, WAs, OSTs, PRDs, OpenSpec changes | English (already required by WA001) |
+| Code identifiers, docblocks, comments in `src/` and `tests/` | English |
+| Release notes and tags | English |
+
+### The one exception
+
+**The French translations of the user documentation.** The `*.fr.md` files under
+`documentation/user/`, and the French canvases and layouts that render them, are **a product for
+readers** — not a working language. They stay French, they stay maintained in parity with their
+English counterpart, and nothing in this agreement invites translating them away.
+
+The distinction that decides any future case is this: *is this text addressed to a user of Durable,
+in a language we chose to serve them in?* If yes, it follows the product. If it is addressed to
+whoever works on Durable — a reviewer, a maintainer, our future selves — it is English.
+
+Two consequences worth stating, because they are the cases that will come up:
+
+- A **French user page has an English source of record.** When the two disagree, the English page is
+  the one that is right, and the French one is a bug to fix — that is what parity means.
+- **Third-party quotations** stay in their original language, as WA001 already allows.
+
+## What this does not do
+
+**It does not rewrite history.** Commit messages already written stay as they are: rewriting them
+would mean rewriting every merged branch, and the value of a readable log does not survive
+invalidating every commit reference in every issue, ADR and journal entry that cites one.
+
+**It is not a mandate to bulk-translate.** Existing French text in scope is debt, and it is listed
+below so that it is visible rather than silent. It gets translated when the file is next edited for
+another reason, or in a change that says so.
+
+### Known debt, on the day this was written
+
+| Where | Extent |
+|---|---|
+| `documentation/audit/` | 22 files, French, landed by #271 — and unknown to `INDEX.md`, `LIFECYCLE.md` and `HUGO.md` |
+| `documentation/journal/inbox/` | 8 entries, French, in a directory WA001 already required to be English |
+| `.worktrees/prises/` | 18 open prise files — 17 French, plus this branch's, which is not — and `PRISES.md` itself |
+| Commit history | French throughout; frozen by the paragraph above |
+
+The pull requests, issues and comments dated 3 September 2026 and later were translated on
+4 September 2026, before this agreement was written. They are the starting point, not part of the
+debt.
+
+## Consequences
+
+- Reviews may reject a non-English addition to any surface in the table above, the same way WA001
+  allows it for documentation.
+- An agent working on this repository writes English by default, and asks before writing anything
+  else. The single exception is narrow enough to name explicitly when it applies.
+- `documentation/audit/` is the first thing this agreement judges, and it judges it
+  non-conforming — in language and in placement. Deciding what happens to it is a follow-up, not a
+  silent grandfathering.
+- Nothing here is enforced by CI today. A guard is possible — a check on the language of a pull
+  request body, or on new files under the paths above — and it is deliberately not part of this
+  agreement: the rule is worth stating before it is worth automating, and WA005 is the reminder that
+  an unenforced rule is still a rule people can follow.
+
+## References
+
+- [WA001 — English language for project documentation](WA001-english-language-documentation.md)
+- [documentation/LIFECYCLE.md](../LIFECYCLE.md)
+- [documentation/INDEX.md](../INDEX.md)