diff --git a/ROADMAP.md b/ROADMAP.md
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@@ -6344,3 +6344,6 @@ Original filing (2026-04-18): the session emitted `SessionStart hook (completed)
 
 422. **Unknown top-level subcommands fall through to chat prompt path instead of returning `unknown_subcommand` error — typos silently send the subcommand string as a chat message to the configured LLM** — dogfooded 2026-05-11 by Jobdori on `b98b9a71` in response to Clawhip pinpoint nudge at `1503215095088676956`. Reproduction: `unset ANTHROPIC_AUTH_TOKEN; export ANTHROPIC_API_KEY=fake-key-for-routing-test; claw completely-bogus-subcommand --output-format json` returns `{"error":"api returned 401 Unauthorized (authentication_error) [trace req_011...]: invalid x-api-key","kind":"api_http_error"}` — proving the unknown token reached the Anthropic API endpoint as a chat prompt. With valid credentials, the bogus subcommand string would be silently consumed as a chat message, billing the user for a typo and producing whatever continuation the LLM generates. **Pre-error path:** `claw <unknown> --output-format json` with no creds returns `kind:"missing_credentials"` (the auth gate fires first), masking the routing bug. Only with creds present does the fallthrough manifest as the actual prompt being sent. **Sibling exit-code bug:** when the chat-path 401 returns, the JSON envelope is `kind:"api_http_error"` but exit code is **0**, while `cli_parse` errors (e.g. `--no-such-flag`) and `missing_credentials` errors correctly exit **1**. Exit-code parity between error envelopes is broken — automation that gates on `$?` will treat the 401-as-chat as success. **Required fix shape:** (a) reserve unknown top-level tokens that match no registered subcommand and emit `kind:"unknown_subcommand"` with `unknown:<token>` field and exit code 1, BEFORE the chat fallback path; (b) when a token is intended as a chat prompt, require an explicit verb (`prompt`, `chat`, `ask`) or `--prompt` flag; (c) ensure exit codes are non-zero for all `kind:*_error` envelopes; (d) regression test: `claw <bogus> --output-format json` with valid auth returns `kind:"unknown_subcommand"` exit 1, never reaches the API. **Why this matters:** automation that calls `claw <subcommand>` with a programmatically constructed verb (typo, version drift, refactored command) silently bills tokens and produces hallucinated output instead of a typed error. Cross-cluster with #108 (CLI fallthrough discovered earlier) — #422 is the post-#108 audit confirming the routing bug still bites with valid credentials. Source: Jobdori live dogfood, `b98b9a71`, 2026-05-11.
 
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+423. **`claw prompt` does not read prompt text from stdin when no positional prompt arg is provided — `echo "what is 2+2" | claw prompt --output-format json` returns `kind:"unknown" error:"prompt subcommand requires a prompt string"` instead of consuming stdin** — dogfooded 2026-05-11 by Jobdori on `3c563fa1` in response to Clawhip pinpoint nudge at `1503222644739276951`. Reproduction: `echo "what is 2+2" | claw prompt --output-format json` → `{"error":"prompt subcommand requires a prompt string","hint":null,"kind":"unknown","type":"error"}` exit 1. Same for `claw prompt --output-format json` with stdin redirected from a file. The most common Unix automation pattern (`cmd | claw prompt`) is broken because the prompt subcommand only reads the positional argument, never falls through to stdin. **Sibling envelope-kind bug:** the error `kind` is `"unknown"` instead of a typed `"missing_argument"` or `"validation_error"`. The `unknown` discriminator is the catch-all bucket — automation that switches on `kind` to differentiate input-validation errors from runtime errors gets no signal here. **Required fix shape:** (a) when `prompt` subcommand has no positional prompt arg AND stdin is not a TTY (i.e., piped or redirected), read stdin to EOF and use that as the prompt; (b) emit `kind:"missing_argument"` (not `"unknown"`) when both positional arg and stdin are absent; (c) add `--prompt-stdin` or `--stdin` opt-in flag for explicit control; (d) regression tests: `echo X | claw prompt --output-format json` reaches the runtime with prompt=X, AND `claw prompt < /dev/null` returns `kind:"missing_argument"` exit 1. **Why this matters:** Unix pipelines are the foundation of CLI automation. Every other major CLI (curl, jq, gh, kubectl) accepts stdin as the primary input when no positional arg is given. Breaking this convention forces automation to either inline the prompt as a shell-quoted string (escaping nightmare for multiline/code) or write to a temp file first. The `kind:"unknown"` error category compounds the problem by making the failure indistinguishable from a runtime crash. Source: Jobdori live dogfood, `3c563fa1`, 2026-05-11.
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