feat(cli+broker): structured argument validation, msg-status prefixes (v1.9.3)

Adds apps/cli/src/cli/validators.ts — a small module of shape
validators (pubkey, pubkey prefix, message id, mesh slug) that return
discriminated results so callers can distinguish "shape is wrong"
(INVALID_ARGS exit) from "value is well-shaped, lookup failed"
(NOT_FOUND exit). Includes renderValidationError() for a consistent
three-tier error contract: what's wrong, what would be valid, closest
valid alternative.

First adopter is `claudemesh msg-status`:
- Validates id locally before opening WS — typos return immediately.
- Accepts 8-32 char prefixes (full ids are 32). Pastes that get
  copy-truncated by the terminal still work.
- Distinct error messages for malformed input vs not-in-queue vs
  ambiguous prefix; --json emits the structured shape.

Broker side: WS message_status handler validates idStr is 8-32
base62 before querying. Prefix lookups use LIKE 'prefix%' scoped to
the caller's mesh (no cross-mesh leak). Returns ambiguous_prefix
when more than one match.

Establishes the canonical pattern; rolling out to send / grant /
revoke / topic post --reply-to in subsequent patches.

apps/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claudemesh-cli",
-  "version": "1.9.2",
+  "version": "1.9.3",
   "description": "Peer mesh for Claude Code sessions — CLI + MCP server.",
   "keywords": [
     "claude-code",

apps/cli/src/cli/validators.ts

@@ -0,0 +1,198 @@
+/**
+ * Argument validators — fail loud at the boundary, with specific reasons.
+ *
+ * Each validator returns a discriminated `ValidationResult` so callers can
+ * branch cleanly between "shape is wrong" (INVALID_ARGS exit) vs "value
+ * is well-shaped, do the lookup" (proceed). Hints (`reason`, `expected`,
+ * `nearest`) drive the three-tier error message contract:
+ *
+ *   1. WHAT'S WRONG — the failed assertion.
+ *   2. WHAT WOULD BE VALID — the canonical shape.
+ *   3. CLOSEST VALID ALTERNATIVE — best-effort suggestion.
+ *
+ * Use these instead of throwing strings or returning `null` for malformed
+ * input. They make argument errors structurally distinct from "thing
+ * doesn't exist" errors, which today's CLI conflates.
+ */
+
+export type ValidationResult<T = string> =
+  | { ok: true; value: T }
+  | { ok: false; code: string; reason: string; expected?: string };
+
+const HEX_RE = /^[0-9a-f]+$/i;
+const BASE62_RE = /^[A-Za-z0-9]+$/;
+const SLUG_RE = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
+
+/**
+ * 64-char lowercase hex peer pubkey (member or session).
+ * Accepts UPPERCASE hex and normalizes to lowercase.
+ */
+export function validatePubkey(input: string | undefined): ValidationResult {
+  if (!input) {
+    return {
+      ok: false,
+      code: "missing",
+      reason: "pubkey is required",
+      expected: "64 lowercase hex chars",
+    };
+  }
+  if (input.length !== 64) {
+    return {
+      ok: false,
+      code: "wrong_length",
+      reason: `pubkey is ${input.length} chars, expected 64`,
+      expected: "64 lowercase hex chars (try `claudemesh peer list --json`)",
+    };
+  }
+  if (!HEX_RE.test(input)) {
+    return {
+      ok: false,
+      code: "non_hex",
+      reason: "pubkey contains non-hex characters",
+      expected: "characters [0-9a-f] only",
+    };
+  }
+  return { ok: true, value: input.toLowerCase() };
+}
+
+/**
+ * Hex pubkey *prefix* — used for short-form references. Min 8 chars
+ * to keep collisions vanishingly rare on a per-mesh roster, max 64.
+ */
+export function validatePubkeyPrefix(
+  input: string | undefined,
+  { min = 8 }: { min?: number } = {},
+): ValidationResult {
+  if (!input) {
+    return {
+      ok: false,
+      code: "missing",
+      reason: "pubkey prefix is required",
+      expected: `${min}-64 lowercase hex chars`,
+    };
+  }
+  if (input.length < min) {
+    return {
+      ok: false,
+      code: "too_short",
+      reason: `prefix is ${input.length} chars, needs ≥${min}`,
+      expected: `${min}+ hex chars (full pubkey is 64)`,
+    };
+  }
+  if (input.length > 64) {
+    return {
+      ok: false,
+      code: "too_long",
+      reason: `prefix is ${input.length} chars, max 64`,
+      expected: "drop trailing characters",
+    };
+  }
+  if (!HEX_RE.test(input)) {
+    return {
+      ok: false,
+      code: "non_hex",
+      reason: "prefix contains non-hex characters",
+      expected: "characters [0-9a-f] only",
+    };
+  }
+  return { ok: true, value: input.toLowerCase() };
+}
+
+/**
+ * Message id — base62, 32 chars exact, OR a prefix of ≥8 chars.
+ * Returns `{ value, isPrefix }` so callers can decide whether to
+ * resolve via lookup or treat as full id.
+ */
+export function validateMessageId(
+  input: string | undefined,
+): ValidationResult<{ value: string; isPrefix: boolean }> {
+  if (!input) {
+    return {
+      ok: false,
+      code: "missing",
+      reason: "message id is required",
+      expected: "32-char base62 id, or ≥8-char prefix",
+    };
+  }
+  if (input.length < 8) {
+    return {
+      ok: false,
+      code: "too_short",
+      reason: `id is ${input.length} chars, needs ≥8`,
+      expected: "8+ chars (paste from a previous send/post output)",
+    };
+  }
+  if (input.length > 32) {
+    return {
+      ok: false,
+      code: "too_long",
+      reason: `id is ${input.length} chars, max 32`,
+      expected: "trim trailing characters",
+    };
+  }
+  if (!BASE62_RE.test(input)) {
+    return {
+      ok: false,
+      code: "bad_charset",
+      reason: "id contains characters outside [A-Za-z0-9]",
+      expected: "base62 only",
+    };
+  }
+  return { ok: true, value: { value: input, isPrefix: input.length < 32 } };
+}
+
+/**
+ * Mesh slug — kebab-case, lowercase, 2-64 chars.
+ */
+export function validateMeshSlug(input: string | undefined): ValidationResult {
+  if (!input) {
+    return {
+      ok: false,
+      code: "missing",
+      reason: "mesh slug is required",
+      expected: "kebab-case slug (e.g. `openclaw`)",
+    };
+  }
+  if (input.length < 2 || input.length > 64) {
+    return {
+      ok: false,
+      code: "wrong_length",
+      reason: `slug is ${input.length} chars, expected 2-64`,
+      expected: "lowercase kebab-case",
+    };
+  }
+  if (!SLUG_RE.test(input)) {
+    return {
+      ok: false,
+      code: "bad_format",
+      reason: "slug must be lowercase letters, digits, and hyphens (no leading/trailing hyphen)",
+      expected: "e.g. `team-alpha`, `flexicar-2`",
+    };
+  }
+  return { ok: true, value: input };
+}
+
+/**
+ * Render a structured validation error to stderr in the canonical
+ * three-line shape: `✘ <verb> <input>` / `   <reason>` / `   <expected>`.
+ *
+ * Optional fourth line for `nearest` when a fuzzy suggestion is available.
+ */
+export function renderValidationError(
+  args: {
+    verb: string;
+    input: string;
+    result: Extract<ValidationResult, { ok: false }>;
+    nearest?: string;
+  },
+  write: (s: string) => void = (s) => process.stderr.write(s),
+): void {
+  write(`  \x1b[31m✘\x1b[0m ${args.verb} ${args.input}\n`);
+  write(`     ${args.result.reason}.\n`);
+  if (args.result.expected) {
+    write(`     expected: ${args.result.expected}\n`);
+  }
+  if (args.nearest) {
+    write(`     did you mean: \x1b[36m${args.nearest}\x1b[0m\n`);
+  }
+}

apps/cli/src/commands/broker-actions.ts

@@ -20,6 +20,7 @@ import { tryBridge } from "~/services/bridge/client.js";
 import { render } from "~/ui/render.js";
 import { bold, clay, dim } from "~/ui/styles.js";
 import { EXIT } from "~/constants/exit-codes.js";
+import { validateMessageId, renderValidationError } from "~/cli/validators.js";
 
 type StateFlags = { mesh?: string; json?: boolean };
 type PeerStatus = "idle" | "working" | "dnd";
@@ -186,15 +187,50 @@ export async function runForget(id: string | undefined, opts: StateFlags): Promi
 // --- msg-status ---
 
 export async function runMsgStatus(id: string | undefined, opts: StateFlags): Promise<number> {
-  if (!id) {
-    render.err("Usage: claudemesh msg-status <message-id>");
+  // Validate input shape *before* we open a WS connection, so a typo
+  // returns a structured error instead of "not found or timed out".
+  const v = validateMessageId(id);
+  if (!v.ok) {
+    if (opts.json) {
+      console.log(
+        JSON.stringify({
+          ok: false,
+          error: "invalid_argument",
+          field: "messageId",
+          code: v.code,
+          reason: v.reason,
+          expected: v.expected,
+        }),
+      );
+    } else {
+      renderValidationError({
+        verb: "msg-status",
+        input: id ?? "(missing)",
+        result: v,
+      });
+    }
     return EXIT.INVALID_ARGS;
   }
+  const lookupId = v.value.value;
   return await withMesh({ meshSlug: opts.mesh ?? null }, async (client) => {
-    const result = await client.messageStatus(id);
+    const result = await client.messageStatus(lookupId);
     if (!result) {
-      if (opts.json) console.log(JSON.stringify({ id, found: false }));
-      else render.err(`Message ${id} not found or timed out.`);
+      if (opts.json) {
+        console.log(
+          JSON.stringify({
+            ok: false,
+            error: "not_found",
+            id: lookupId,
+            isPrefix: v.value.isPrefix,
+          }),
+        );
+      } else {
+        const hint = v.value.isPrefix
+          ? `   no message id starts with ${dim("\"" + lookupId + "\"")} in this mesh.\n   try: claudemesh msg-status <full-32-char-id>`
+          : `   message ${dim(lookupId.slice(0, 12) + "…")} not in queue (already drained, expired, or never sent in this mesh).`;
+        render.err(`message not found`);
+        process.stderr.write(hint + "\n");
+      }
       return EXIT.NOT_FOUND;
     }
     if (opts.json) {