feat: add hostname to hello + local/remote peer locality detection

Peers report os.hostname() in the hello handshake. list_peers shows
[local] or [remote] tag per peer. MCP instructions teach AI to read
local peers' files directly via filesystem instead of relay.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/broker/src/index.ts

@@ -101,6 +101,7 @@ interface PeerConn {
   sessionPubkey: string | null;
   displayName: string;
   cwd: string;
+  hostname?: string;
   peerType?: "ai" | "human" | "connector";
   channel?: string;
   model?: string;
@@ -920,6 +921,7 @@ async function handleHello(
     sessionPubkey: hello.sessionPubkey ?? null,
     displayName: effectiveDisplayName,
     cwd: hello.cwd,
+    hostname: hello.hostname,
     peerType: hello.peerType,
     channel: hello.channel,
     model: hello.model,
@@ -1138,6 +1140,7 @@ function handleConnection(ws: WebSocket): void {
                 sessionId: p.sessionId,
                 connectedAt: p.connectedAt.toISOString(),
                 cwd: pc?.cwd ?? p.cwd,
+                ...(pc?.hostname ? { hostname: pc.hostname } : {}),
                 ...(pc?.peerType ? { peerType: pc.peerType } : {}),
                 ...(pc?.channel ? { channel: pc.channel } : {}),
                 ...(pc?.model ? { model: pc.model } : {}),

apps/broker/src/types.ts

@@ -57,6 +57,8 @@ export interface WSHelloMessage {
   sessionId: string;
   pid: number;
   cwd: string;
+  /** OS hostname — used to detect same-machine peers for direct file access. */
+  hostname?: string;
   /** Peer type: ai session, human user, or external connector. */
   peerType?: "ai" | "human" | "connector";
   /** Channel the peer connected from (e.g. "claude-code", "telegram", "slack", "web"). */
@@ -226,6 +228,7 @@ export interface WSPeersListMessage {
     sessionId: string;
     connectedAt: string;
     cwd?: string;
+    hostname?: string;
     peerType?: "ai" | "human" | "connector";
     channel?: string;
     model?: string;

apps/cli/src/mcp/server.ts

@@ -228,6 +228,11 @@ Persistent knowledge that survives across sessions. Use remember(content, tags?)
 share_file for persistent references, send_message(file:) for ephemeral attachments.
 Tags on shared files make them searchable. Use list_files to find what peers shared.
 
+## Peer project files
+read_peer_file and list_peer_files request files from remote peers through the mesh (1MB limit, base64 relay).
+**Same-machine shortcut:** If a peer's \`hostname\` matches yours (visible in list_peers), they are a LOCAL peer — read their files directly via the filesystem using their \`cwd\` path. Faster, no size limit, no relay. Use read_peer_file only for REMOTE peers (different hostname).
+Each peer in list_peers shows a \`locality\` tag: "local" (same machine, direct filesystem access) or "remote" (different machine, use read_peer_file).
+
 ## Vectors
 Store and search semantic embeddings. Use vector_store to index content, vector_search to find similar content.
 
@@ -342,10 +347,12 @@ Your message mode is "${messageMode}".
               if (p.model) meta.push(`model:${p.model}`);
               const metaStr = meta.length ? ` {${meta.join(", ")}}` : "";
               const cwdStr = p.cwd ? ` cwd:${p.cwd}` : "";
+              const locality = p.hostname && p.hostname === require("os").hostname() ? "local" : "remote";
+              const localityTag = ` [${locality}]`;
               const profileAvatar = p.profile?.avatar ? `${p.profile.avatar} ` : "";
               const profileTitle = p.profile?.title ? ` (${p.profile.title})` : "";
               const hiddenTag = p.visible === false ? " [hidden]" : "";
-              return `- ${profileAvatar}**${p.displayName}**${profileTitle} [${p.status}]${hiddenTag}${groupsStr}${metaStr} (${p.pubkey.slice(0, 12)}…)${cwdStr}${summary}`;
+              return `- ${profileAvatar}**${p.displayName}**${profileTitle} [${p.status}]${localityTag}${hiddenTag}${groupsStr}${metaStr} (${p.pubkey.slice(0, 12)}…)${cwdStr}${summary}`;
             });
             sections.push(`${header}\n${peerLines.join("\n")}`);
           }

apps/cli/src/ws/client.ts

@@ -35,6 +35,7 @@ export interface PeerInfo {
   sessionId: string;
   connectedAt: string;
   cwd?: string;
+  hostname?: string;
   peerType?: "ai" | "human" | "connector";
   channel?: string;
   model?: string;
@@ -194,6 +195,7 @@ export class BrokerClient {
               sessionId: `${process.pid}-${Date.now()}`,
               pid: process.pid,
               cwd: process.cwd(),
+              hostname: require("os").hostname(),
               peerType: "ai" as const,
               channel: "claude-code",
               model: process.env.CLAUDE_MODEL || undefined,