diff --git a/12-Claude-to-OpenCode.md b/12-Claude-to-OpenCode.md
index 8e8d544..f9bf5a8 100644
--- a/12-Claude-to-OpenCode.md
+++ b/12-Claude-to-OpenCode.md
@@ -84,6 +84,58 @@ OpenCode substitutes at load time, in both `headers` and `environment`:
 This is what makes `opencode.json` safe to commit — and it **must** be committable, because a peer
 running in a git worktree receives tracked files only. No credential ever belongs in the file.
 
+**The trap: `{env:…}` reads OpenCode's process environment, and OpenCode has no env store of its
+own.** Claude Code supplies this project's secrets through `env` blocks in its settings cascade —
+files opencode never reads. Verified here: a clean login shell
+(`env -u VAR zsh -lc …`) has none of `CONTEXT7_TOKEN`, `GITEA_ACCESS_TOKEN`, `GITEA_HOST`; they
+exist only inside processes Claude Code spawned. Run `opencode mcp list` from such a process and
+everything is green; run it from a real terminal and context7 is `⚠ needs authentication`.
+
+Worse, the two launch paths disagree on names. A bridge-spawned worker gets `GITEA_TOKEN` +
+`GITEA_HOST` from `applyGitToken` (see [Features](11-Features) → the git-forge token grant), not
+`GITEA_ACCESS_TOKEN` — so an `opencode.json` written against the terminal's environment fails
+inside a worker, and vice versa.
+
+So the supply route follows from who launches opencode:
+
+| Launcher | Route | Here |
+|---|---|---|
+| a human, from a terminal | `{file:.secrets/…}` | gitignored `.secrets/`, workspace-scoped |
+| a bridge-spawned worker | `{env:…}` | `applyGitToken` + the profile's `env:` block |
+
+For the terminal case this repo uses `{file:}` with **workspace-relative** paths — verified: opencode
+resolves them against the project root, so no shell export and no direnv is needed, and the secret
+never enters an rc file that every process inherits.
+
+`.secrets/` being gitignored is the point *and* the limitation: a worker in a git worktree does not
+receive it, by the same tracked-files-only rule that makes `opencode.json` worth committing. Workers
+are fed by the launcher instead — which is also where the name mismatch above must be reconciled.
+
+### Keeping Claude Code on the same source of truth
+
+Claude Code expands `${VAR}` in `.mcp.json` but cannot read a file, so left alone it needs the same
+tokens duplicated as literals in `.claude/settings.local.json`. A committed `.autoenv` (directory-scoped
+env loader — `autoenv` here, `direnv` elsewhere) closes that gap by exporting `.secrets/` into the
+environment, holding no secret of its own:
+
+```mermaid
+flowchart LR
+    S[".secrets/<br/>(gitignored, 0600)"]
+    S -->|"{file:...}"| OC["opencode.json"]
+    S -->|".autoenv exports"| E["process env"]
+    E -->|"${VAR}"| MJ[".mcp.json"]
+    L["launcher env"] -->|"{env:...}"| WK["spawned worker"]
+    classDef warn fill:#b7791f,stroke:#7b341e,color:#ffffff;
+    class L warn
+```
+
+*One store, three readers — the worker path stays separate because a worktree has no `.secrets/`.*
+
+Two verified caveats. The loader fires on entering the directory **and** when a shell starts there,
+so a terminal opened directly in the repo is covered — but a Claude Code launched outside a login
+shell is not, and an unset `${VAR}` degrades silently to the literal text `${VAR}` rather than
+failing. And leaving the directory does not unload the variables unless leave-files are enabled.
+
 ## What must never cross
 
 Machine-local MCP servers — an IDE index, a language server, an editor bridge. A committed project
@@ -101,8 +153,11 @@ A file on disk proves nothing about what the agent loaded.
 opencode run "In one line: state a rule from this project's instructions."
 ```
 
-The answer must reflect the real `CLAUDE.md`. Then list the MCP servers and confirm each expected
-one is connected — and that nothing you withheld appears.
+The answer must reflect the real `CLAUDE.md`. Then `opencode mcp list` — and treat its verdict with
+suspicion: **"connected" does not mean "working"**. A stdio server missing its credential completes
+the handshake and reports green; only a tool call exposes it. Verified: `gitea` showed
+`✓ connected` with no token, then failed the first call with `token is required`. Exercise one
+authenticated tool per server, and confirm nothing you withheld appears.
 
 ## Gotchas