feat: add platform key usage to mcp auth

Cargo.lock

@@ -1168,6 +1168,7 @@ name = "mcp-server"
 version = "0.1.0"
 dependencies = [
  "axum",
+ "base64",
  "crank-adapter-grpc",
  "crank-core",
  "crank-mapping",
@@ -1177,6 +1178,7 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_json",
+ "sha2",
  "sqlx",
  "time",
  "tokio",

TASKS.md

@@ -2,15 +2,14 @@
 
 ## Current
 
-### `feat/demo-assets`
+### `feat/platform-key-usage`
 
-Status: in_progress
+Status: completed
 
 DoD:
-- project has an idempotent PostgreSQL demo seed for live UI screens
-- demo seed fills workspaces, memberships, invitations, operations, agents, keys and usage
-- seed is controlled by env and does not live in migrations
-- docs explain how to enable and use demo data
+- platform API keys authenticate real machine access
+- `last_used_at` updates from successful platform key usage
+- UI API keys page reflects honest runtime usage rather than seed-only metadata
 
 ## Next
 
@@ -18,6 +17,4 @@ DoD:
 
 ## Backlog
 
-- `feat/current-workspace-session-model`
-- `feat/agent-lifecycle-polish`
-- `feat/platform-key-usage`
+- `feat/alpine-polish`

apps/mcp-server/Cargo.toml

@@ -7,12 +7,14 @@ version.workspace = true
 
 [dependencies]
 axum.workspace = true
+base64.workspace = true
 crank-core = { path = "../../crates/crank-core" }
 crank-registry = { path = "../../crates/crank-registry" }
 crank-runtime = { path = "../../crates/crank-runtime" }
 crank-schema = { path = "../../crates/crank-schema" }
 serde.workspace = true
 serde_json.workspace = true
+sha2.workspace = true
 time.workspace = true
 tokio = { workspace = true, features = ["sync"] }
 tracing.workspace = true

apps/mcp-server/src/app.rs

@@ -8,18 +8,21 @@ use axum::{
     extract::{Path, State},
     http::{
         HeaderMap, HeaderValue, StatusCode,
-        header::{self, ACCEPT},
+        header::{self, ACCEPT, AUTHORIZATION},
     },
     response::{IntoResponse, Response},
     routing::get,
 };
+use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD};
 use crank_core::{
     InvocationLevel, InvocationLog, InvocationLogId, InvocationSource, InvocationStatus,
+    PlatformApiKeyScope,
 };
 use crank_registry::{CreateInvocationLogRequest, PostgresRegistry, PublishedAgentTool};
 use crank_runtime::{RuntimeError, RuntimeExecutor, RuntimeOperation};
 use serde::{Deserialize, Serialize};
 use serde_json::{Value, json};
+use sha2::{Digest, Sha256};
 use time::{OffsetDateTime, format_description::well_known::Rfc3339};
 
 use crate::{
@@ -106,6 +109,12 @@ async fn mcp_delete(
     State(state): State<Arc<AppState>>,
     headers: HeaderMap,
 ) -> Response {
+    if let Err(status) =
+        require_platform_api_key(&state, &path, &headers, PlatformApiKeyScope::Read).await
+    {
+        return status.into_response();
+    }
+
     match session_id_from_headers(&headers) {
         Ok(Some(session_id)) => match state.sessions.get(&session_id).await {
             Some(session)
@@ -149,6 +158,14 @@ async fn mcp_post(
         Err(status) => return status.into_response(),
     };
 
+    let required_scope = match method_name(&message) {
+        Some("tools/call") => PlatformApiKeyScope::Write,
+        _ => PlatformApiKeyScope::Read,
+    };
+    if let Err(status) = require_platform_api_key(&state, &path, &headers, required_scope).await {
+        return status.into_response();
+    }
+
     match method_name(&message) {
         Some("initialize") if is_request(&message) => {
             handle_initialize(state, &path, &message).await
@@ -467,6 +484,71 @@ async fn require_initialized_session(
     Ok(session)
 }
 
+async fn require_platform_api_key(
+    state: &Arc<AppState>,
+    path: &AgentRoutePath,
+    headers: &HeaderMap,
+    required_scope: PlatformApiKeyScope,
+) -> Result<(), StatusCode> {
+    let secret = bearer_token(headers).ok_or(StatusCode::UNAUTHORIZED)?;
+    let secret_hash = hash_access_secret(secret);
+    let Some(api_key) = state
+        .registry
+        .get_platform_api_key_by_secret_for_workspace_slug(&path.workspace_slug, &secret_hash)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
+    else {
+        return Err(StatusCode::UNAUTHORIZED);
+    };
+
+    if !allows_scope(&api_key.api_key.scopes, required_scope) {
+        return Err(StatusCode::FORBIDDEN);
+    }
+
+    let used_at = OffsetDateTime::now_utc()
+        .format(&Rfc3339)
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+    state
+        .registry
+        .touch_platform_api_key(&api_key.api_key.workspace_id, &api_key.api_key.id, &used_at)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    Ok(())
+}
+
+fn bearer_token(headers: &HeaderMap) -> Option<&str> {
+    let value = headers.get(AUTHORIZATION)?.to_str().ok()?;
+    let (scheme, token) = value.split_once(' ')?;
+    if !scheme.eq_ignore_ascii_case("Bearer") || token.is_empty() {
+        return None;
+    }
+
+    Some(token)
+}
+
+fn allows_scope(scopes: &[PlatformApiKeyScope], required_scope: PlatformApiKeyScope) -> bool {
+    match required_scope {
+        PlatformApiKeyScope::Read => scopes.iter().any(|scope| {
+            matches!(
+                scope,
+                PlatformApiKeyScope::Read
+                    | PlatformApiKeyScope::Write
+                    | PlatformApiKeyScope::Deploy
+            )
+        }),
+        PlatformApiKeyScope::Write => scopes.iter().any(|scope| {
+            matches!(
+                scope,
+                PlatformApiKeyScope::Write | PlatformApiKeyScope::Deploy
+            )
+        }),
+        PlatformApiKeyScope::Deploy => scopes
+            .iter()
+            .any(|scope| matches!(scope, PlatformApiKeyScope::Deploy)),
+    }
+}
+
 fn validate_origin(
     allowed_origins: &AllowedOrigins,
     headers: &HeaderMap,
@@ -611,6 +693,11 @@ fn runtime_error_code(error: &RuntimeError) -> &'static str {
     }
 }
 
+fn hash_access_secret(secret: &str) -> String {
+    let digest = Sha256::digest(secret.as_bytes());
+    URL_SAFE_NO_PAD.encode(digest)
+}
+
 fn json_response(
     status: StatusCode,
     payload: Value,

apps/mcp-server/src/main.rs

@@ -49,19 +49,22 @@ mod tests {
     };
 
     use axum::{Json, Router, http::header, routing::post};
+    use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD};
     use crank_adapter_grpc::test_support as grpc_test_support;
     use crank_core::{
         Agent, AgentId, AgentOperationBinding, AgentStatus, AgentVersion, DescriptorId,
         ExecutionConfig, GraphqlOperationType, GraphqlTarget, GrpcTarget, HttpMethod, Operation,
-        OperationId, OperationStatus, Protocol, RestTarget, Target, ToolDescription, WorkspaceId,
+        OperationId, OperationStatus, PlatformApiKey, PlatformApiKeyId, PlatformApiKeyScope,
+        PlatformApiKeyStatus, Protocol, RestTarget, Target, ToolDescription, WorkspaceId,
     };
     use crank_mapping::{MappingRule, MappingSet};
     use crank_registry::{
-        CreateAgentRequest, ListInvocationLogsQuery, PostgresRegistry, PublishAgentRequest,
-        PublishRequest,
+        CreateAgentRequest, CreatePlatformApiKeyRequest, ListInvocationLogsQuery, PostgresRegistry,
+        PublishAgentRequest, PublishRequest,
     };
     use crank_schema::{Schema, SchemaKind};
     use serde_json::{Value, json};
+    use sha2::{Digest, Sha256};
     use sqlx::{Executor, postgres::PgPoolOptions};
     use tokio::net::TcpListener;
 
@@ -96,6 +99,12 @@ mod tests {
             .await
             .unwrap();
         publish_agent_for_operation(&registry, &operation, "sales-rest").await;
+        let api_key = create_platform_api_key(
+            &registry,
+            "mcp-rest",
+            &[PlatformApiKeyScope::Read, PlatformApiKeyScope::Write],
+        )
+        .await;
 
         let base_url = spawn_mcp_server(build_app(
             registry.clone(),
@@ -105,11 +114,12 @@ mod tests {
         .await;
         let client = reqwest::Client::new();
         let mcp_url = agent_mcp_url(&base_url, "sales-rest");
-        let initialized_session = initialize_session(&client, &mcp_url).await;
+        let initialized_session = initialize_session(&client, &mcp_url, &api_key).await;
 
         let tools = post_jsonrpc(
             &client,
             &mcp_url,
+            &api_key,
             Some(&initialized_session),
             json!({
                 "jsonrpc": "2.0",
@@ -122,6 +132,7 @@ mod tests {
         let call_result = post_jsonrpc(
             &client,
             &mcp_url,
+            &api_key,
             Some(&initialized_session),
             json!({
                 "jsonrpc": "2.0",
@@ -165,6 +176,12 @@ mod tests {
         );
         assert_eq!(logs[0].log.status, crank_core::InvocationStatus::Ok);
         assert_eq!(logs[0].log.tool_name, "crm_create_lead");
+
+        let keys = registry
+            .list_platform_api_keys(&test_workspace_id())
+            .await
+            .unwrap();
+        assert!(keys[0].api_key.last_used_at.is_some());
     }
 
     #[tokio::test]
@@ -188,6 +205,12 @@ mod tests {
             .await
             .unwrap();
         publish_agent_for_operation(&registry, &operation, "sales-graphql").await;
+        let api_key = create_platform_api_key(
+            &registry,
+            "mcp-graphql",
+            &[PlatformApiKeyScope::Read, PlatformApiKeyScope::Write],
+        )
+        .await;
 
         let base_url = spawn_mcp_server(build_app(
             registry,
@@ -197,11 +220,12 @@ mod tests {
         .await;
         let client = reqwest::Client::new();
         let mcp_url = agent_mcp_url(&base_url, "sales-graphql");
-        let initialized_session = initialize_session(&client, &mcp_url).await;
+        let initialized_session = initialize_session(&client, &mcp_url, &api_key).await;
 
         let call_result = post_jsonrpc(
             &client,
             &mcp_url,
+            &api_key,
             Some(&initialized_session),
             json!({
                 "jsonrpc": "2.0",
@@ -245,6 +269,12 @@ mod tests {
             .await
             .unwrap();
         publish_agent_for_operation(&registry, &operation, "sales-grpc").await;
+        let api_key = create_platform_api_key(
+            &registry,
+            "mcp-grpc",
+            &[PlatformApiKeyScope::Read, PlatformApiKeyScope::Write],
+        )
+        .await;
 
         let base_url = spawn_mcp_server(build_app(
             registry,
@@ -254,11 +284,12 @@ mod tests {
         .await;
         let client = reqwest::Client::new();
         let mcp_url = agent_mcp_url(&base_url, "sales-grpc");
-        let initialized_session = initialize_session(&client, &mcp_url).await;
+        let initialized_session = initialize_session(&client, &mcp_url, &api_key).await;
 
         let call_result = post_jsonrpc(
             &client,
             &mcp_url,
+            &api_key,
             Some(&initialized_session),
             json!({
                 "jsonrpc": "2.0",
@@ -284,6 +315,9 @@ mod tests {
     #[tokio::test]
     async fn requires_initialized_notification_before_tool_methods() {
         let registry = test_registry().await;
+        publish_agent_with_bindings(&registry, "sales-init", vec![]).await;
+        let api_key =
+            create_platform_api_key(&registry, "mcp-init", &[PlatformApiKeyScope::Read]).await;
         let base_url = spawn_mcp_server(build_app(
             registry,
             Duration::from_millis(0),
@@ -295,6 +329,7 @@ mod tests {
         let initialize_response = client
             .post(&mcp_url)
             .header(header::ACCEPT, "application/json, text/event-stream")
+            .header(header::AUTHORIZATION, format!("Bearer {api_key}"))
             .json(&json!({
                 "jsonrpc": "2.0",
                 "id": 1,
@@ -316,6 +351,7 @@ mod tests {
         let tools_list = client
             .post(&mcp_url)
             .header(header::ACCEPT, "application/json, text/event-stream")
+            .header(header::AUTHORIZATION, format!("Bearer {api_key}"))
             .header("MCP-Session-Id", session_id)
             .header("MCP-Protocol-Version", "2025-11-25")
             .json(&json!({
@@ -346,11 +382,18 @@ mod tests {
         .await;
         let client = reqwest::Client::new();
         let mcp_url = agent_mcp_url(&base_url, "sales-refresh");
-        let initialized_session = initialize_session(&client, &mcp_url).await;
+        let api_key = create_platform_api_key(
+            &registry,
+            "mcp-refresh",
+            &[PlatformApiKeyScope::Read, PlatformApiKeyScope::Write],
+        )
+        .await;
+        let initialized_session = initialize_session(&client, &mcp_url, &api_key).await;
 
         let before_publish = post_jsonrpc(
             &client,
             &mcp_url,
+            &api_key,
             Some(&initialized_session),
             json!({
                 "jsonrpc": "2.0",
@@ -381,6 +424,7 @@ mod tests {
         let after_publish = post_jsonrpc(
             &client,
             &mcp_url,
+            &api_key,
             Some(&initialized_session),
             json!({
                 "jsonrpc": "2.0",
@@ -434,6 +478,12 @@ mod tests {
             vec![binding_for_operation(&operation_b)],
         )
         .await;
+        let api_key = create_platform_api_key(
+            &registry,
+            "mcp-agents",
+            &[PlatformApiKeyScope::Read, PlatformApiKeyScope::Write],
+        )
+        .await;
 
         let base_url = spawn_mcp_server(build_app(
             registry,
@@ -444,12 +494,13 @@ mod tests {
         let client = reqwest::Client::new();
         let agent_a_url = agent_mcp_url(&base_url, "sales-a");
         let agent_b_url = agent_mcp_url(&base_url, "sales-b");
-        let session_a = initialize_session(&client, &agent_a_url).await;
-        let session_b = initialize_session(&client, &agent_b_url).await;
+        let session_a = initialize_session(&client, &agent_a_url, &api_key).await;
+        let session_b = initialize_session(&client, &agent_b_url, &api_key).await;
 
         let tools_a = post_jsonrpc(
             &client,
             &agent_a_url,
+            &api_key,
             Some(&session_a),
             json!({
                 "jsonrpc": "2.0",
@@ -462,6 +513,7 @@ mod tests {
         let tools_b = post_jsonrpc(
             &client,
             &agent_b_url,
+            &api_key,
             Some(&session_b),
             json!({
                 "jsonrpc": "2.0",
@@ -476,10 +528,97 @@ mod tests {
         assert_eq!(tools_b["result"]["tools"][0]["name"], "crm_update_lead");
     }
 
-    async fn initialize_session(client: &reqwest::Client, mcp_url: &str) -> String {
+    #[tokio::test]
+    async fn rejects_initialize_without_platform_api_key() {
+        let registry = test_registry().await;
+        publish_agent_with_bindings(&registry, "sales-auth", vec![]).await;
+        let base_url = spawn_mcp_server(build_app(
+            registry,
+            Duration::from_millis(0),
+            Some("https://crank.example.com".to_owned()),
+        ))
+        .await;
+        let client = reqwest::Client::new();
+        let response = client
+            .post(agent_mcp_url(&base_url, "sales-auth"))
+            .header(header::ACCEPT, "application/json, text/event-stream")
+            .json(&json!({
+                "jsonrpc": "2.0",
+                "id": 1,
+                "method": "initialize",
+                "params": {
+                    "protocolVersion": "2025-11-25"
+                }
+            }))
+            .send()
+            .await
+            .unwrap();
+
+        assert_eq!(response.status(), reqwest::StatusCode::UNAUTHORIZED);
+    }
+
+    #[tokio::test]
+    async fn rejects_tool_call_with_read_only_platform_api_key() {
+        let registry = test_registry().await;
+        let upstream_base_url = spawn_upstream_server().await;
+        let operation = test_operation(&upstream_base_url, "crm_read_only");
+
+        registry
+            .create_operation(&test_workspace_id(), &operation, Some("alice"))
+            .await
+            .unwrap();
+        registry
+            .publish_operation(PublishRequest {
+                workspace_id: &test_workspace_id(),
+                operation_id: &operation.id,
+                version: 1,
+                published_at: "2026-03-26T10:00:00Z",
+                published_by: Some("alice"),
+            })
+            .await
+            .unwrap();
+        publish_agent_for_operation(&registry, &operation, "sales-read-only").await;
+        let api_key =
+            create_platform_api_key(&registry, "mcp-read", &[PlatformApiKeyScope::Read]).await;
+
+        let base_url = spawn_mcp_server(build_app(
+            registry,
+            Duration::from_millis(0),
+            Some("https://crank.example.com".to_owned()),
+        ))
+        .await;
+        let client = reqwest::Client::new();
+        let mcp_url = agent_mcp_url(&base_url, "sales-read-only");
+        let initialized_session = initialize_session(&client, &mcp_url, &api_key).await;
+        let response = client
+            .post(&mcp_url)
+            .header(header::ACCEPT, "application/json, text/event-stream")
+            .header(header::AUTHORIZATION, format!("Bearer {api_key}"))
+            .header("MCP-Session-Id", initialized_session)
+            .header("MCP-Protocol-Version", "2025-11-25")
+            .json(&json!({
+                "jsonrpc": "2.0",
+                "id": 3,
+                "method": "tools/call",
+                "params": {
+                    "name": "crm_read_only",
+                    "arguments": {
+                        "email": "user@example.com"
+                    }
+                }
+            }))
+            .send()
+            .await
+            .unwrap();
+
+        assert_eq!(response.status(), reqwest::StatusCode::FORBIDDEN);
+    }
+
+    async fn initialize_session(client: &reqwest::Client, mcp_url: &str, api_key: &str) -> String {
         let initialize_response = client
             .post(mcp_url)
             .header(header::ACCEPT, "application/json, text/event-stream")
+            .header(header::AUTHORIZATION, format!("Bearer {api_key}"))
             .json(&json!({
                 "jsonrpc": "2.0",
                 "id": 1,
@@ -502,6 +641,7 @@ mod tests {
         let initialized_response = client
             .post(mcp_url)
             .header(header::ACCEPT, "application/json, text/event-stream")
+            .header(header::AUTHORIZATION, format!("Bearer {api_key}"))
             .header("MCP-Session-Id", &session_id)
             .header("MCP-Protocol-Version", "2025-11-25")
             .json(&json!({
@@ -521,12 +661,14 @@ mod tests {
     async fn post_jsonrpc(
         client: &reqwest::Client,
         mcp_url: &str,
+        api_key: &str,
         session_id: Option<&str>,
         payload: Value,
     ) -> Value {
         let mut request = client
             .post(mcp_url)
             .header(header::ACCEPT, "application/json, text/event-stream")
+            .header(header::AUTHORIZATION, format!("Bearer {api_key}"))
             .header("MCP-Protocol-Version", "2025-11-25");
 
         if let Some(session_id) = session_id {
@@ -543,6 +685,39 @@ mod tests {
             .unwrap()
     }
 
+    async fn create_platform_api_key(
+        registry: &PostgresRegistry,
+        name: &str,
+        scopes: &[PlatformApiKeyScope],
+    ) -> String {
+        let secret = format!("crk_{}_{}", name, uuid::Uuid::now_v7().simple());
+        let api_key = PlatformApiKey {
+            id: PlatformApiKeyId::new(format!("pk_{name}")),
+            workspace_id: test_workspace_id(),
+            name: name.to_owned(),
+            prefix: secret.chars().take(16).collect(),
+            scopes: scopes.to_vec(),
+            status: PlatformApiKeyStatus::Active,
+            created_at: "2026-03-26T10:00:00Z".to_owned(),
+            last_used_at: None,
+        };
+
+        registry
+            .create_platform_api_key(CreatePlatformApiKeyRequest {
+                api_key: &api_key,
+                secret_hash: &hash_access_secret(&secret),
+            })
+            .await
+            .unwrap();
+
+        secret
+    }
+
+    fn hash_access_secret(secret: &str) -> String {
+        let digest = Sha256::digest(secret.as_bytes());
+        URL_SAFE_NO_PAD.encode(digest)
+    }
+
     async fn spawn_upstream_server() -> String {
         let app = Router::new().route("/crm/leads", post(create_lead));
         let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();

apps/ui/html/api-keys.html

@@ -115,7 +115,7 @@
     <div class="page-header">
       <div class="page-header-text">
         <h1 class="page-title" data-i18n="apikeys.title">API Keys</h1>
-        <p class="page-subtitle">Keys authenticate external clients and CI pipelines to the Crank API.</p>
+        <p class="page-subtitle">Keys authenticate external MCP clients and workspace automation against Crank.</p>
       </div>
       <div class="page-header-actions">
         <button class="btn-primary" id="btn-create-key" type="button">
@@ -131,7 +131,7 @@
         <path d="M8 11V8M8 5.5V5"/>
       </svg>
       <div>
-        <strong>Keys are only shown once.</strong> Copy and store them securely immediately after creation — Crank stores only a hash. Revoked keys cannot be restored.
+        <strong>Keys are only shown once.</strong> Copy and store them securely immediately after creation — Crank stores only a hash. `Last used` updates after successful MCP authentication.
       </div>
     </div>
 
@@ -175,19 +175,19 @@
           <div style="font-size:12.5px;font-weight:600;color:var(--text-primary);margin-bottom:4px;display:flex;align-items:center;gap:6px;">
             <span class="badge badge-scope">read</span>
           </div>
-          <div style="font-size:12px;color:var(--text-muted);line-height:1.55;">List operations, read configs, query logs and usage metrics.</div>
+          <div style="font-size:12px;color:var(--text-muted);line-height:1.55;">Initialize MCP sessions, ping the server, and list tools for a workspace agent.</div>
         </div>
         <div>
           <div style="font-size:12.5px;font-weight:600;color:var(--text-primary);margin-bottom:4px;">
             <span class="badge badge-scope">write</span>
           </div>
-          <div style="font-size:12px;color:var(--text-muted);line-height:1.55;">Create, update, and delete operations and their configurations.</div>
+          <div style="font-size:12px;color:var(--text-muted);line-height:1.55;">Execute `tools/call` requests against published agent toolsets.</div>
         </div>
         <div>
           <div style="font-size:12.5px;font-weight:600;color:var(--text-primary);margin-bottom:4px;">
             <span class="badge badge-scope">deploy</span>
           </div>
-          <div style="font-size:12px;color:var(--text-muted);line-height:1.55;">Publish agents and operations and perform deploy-scoped platform actions.</div>
+          <div style="font-size:12px;color:var(--text-muted);line-height:1.55;">Reserved for deploy-scoped automation. Today it also permits MCP read/write flows.</div>
         </div>
       </div>
     </div>

apps/ui/js/api-keys.js

@@ -5,9 +5,9 @@ var search = '';
 
 var SCOPES = ['read', 'write', 'deploy'];
 var SCOPE_DESC = {
-  read: 'Read operations, logs, and usage',
-  write: 'Create and update operations',
-  deploy: 'Publish agents and operations',
+  read: 'Initialize MCP sessions and list tools',
+  write: 'Execute published tools through MCP',
+  deploy: 'Reserved for deploy-scoped automation',
 };
 
 function mapKeyRecord(record) {

crates/crank-registry/src/postgres.rs

@@ -584,6 +584,36 @@ impl PostgresRegistry {
         rows.iter().map(map_platform_api_key_record).collect()
     }
 
+    pub async fn get_platform_api_key_by_secret_for_workspace_slug(
+        &self,
+        workspace_slug: &str,
+        secret_hash: &str,
+    ) -> Result<Option<PlatformApiKeyRecord>, RegistryError> {
+        let row = sqlx::query(
+            "select
+                k.id,
+                k.workspace_id,
+                k.name,
+                k.prefix,
+                k.scopes_json,
+                k.status,
+                to_char(k.created_at at time zone 'UTC', 'YYYY-MM-DD\"T\"HH24:MI:SS\"Z\"') as created_at,
+                to_char(k.last_used_at at time zone 'UTC', 'YYYY-MM-DD\"T\"HH24:MI:SS\"Z\"') as last_used_at
+             from platform_api_keys k
+             join workspaces w on w.id = k.workspace_id
+             where w.slug = $1
+               and k.secret_hash = $2
+               and k.status = 'active'
+             limit 1",
+        )
+        .bind(workspace_slug)
+        .bind(secret_hash)
+        .fetch_optional(&self.pool)
+        .await?;
+
+        row.as_ref().map(map_platform_api_key_record).transpose()
+    }
+
     pub async fn create_platform_api_key(
         &self,
         request: CreatePlatformApiKeyRequest<'_>,
@@ -680,6 +710,32 @@ impl PostgresRegistry {
         Ok(())
     }
 
+    pub async fn touch_platform_api_key(
+        &self,
+        workspace_id: &WorkspaceId,
+        key_id: &PlatformApiKeyId,
+        used_at: &str,
+    ) -> Result<(), RegistryError> {
+        let result = sqlx::query(
+            "update platform_api_keys
+                set last_used_at = $3::timestamptz
+              where workspace_id = $1 and id = $2",
+        )
+        .bind(workspace_id.as_str())
+        .bind(key_id.as_str())
+        .bind(used_at)
+        .execute(&self.pool)
+        .await?;
+
+        if result.rows_affected() == 0 {
+            return Err(RegistryError::PlatformApiKeyNotFound {
+                key_id: key_id.as_str().to_owned(),
+            });
+        }
+
+        Ok(())
+    }
+
     pub async fn create_invocation_log(
         &self,
         request: CreateInvocationLogRequest<'_>,

docs/admin-api.md

@@ -145,6 +145,7 @@
 - `POST /platform-api-keys` возвращает metadata ключа и одноразовый `secret`;
 - `secret` доступен только в create-response;
 - list endpoints возвращают только metadata, `prefix`, `status`, `scopes` и `last_used_at`.
+- `last_used_at` обновляется при успешной machine-auth аутентификации этим ключом в `mcp-server`.
 
 ### 5.8. Observability
 

docs/alpine-ui-integration-plan.md

@@ -201,7 +201,6 @@ UI-файлы:
 
 Что еще не хватает:
 
-- отдельный usage/last-used update flow, когда ключи реально начнут использоваться в runtime;
 - если захотим richer UX, можно добавить server-side pagination и фильтрацию по статусу.
 
 Отдельный конфликт:
@@ -213,7 +212,8 @@ UI-файлы:
 
 - страница уже сажается на текущий backend без новых ручек;
 - live `list/create/revoke/delete` можно считать закрытым;
-- следующий реальный шаг здесь только в polishing вокруг usage и audit trail.
+- `last_used_at` теперь обновляется через успешную machine-auth аутентификацию в `mcp-server`;
+- следующий реальный шаг здесь только в polishing вокруг audit trail и richer filtering.
 
 ### 4.5. Logs
 

docs/mcp-interface.md

@@ -93,6 +93,19 @@
 - конкретный curated toolset;
 - набор usage и log labels.
 
+## 7.1. MCP authentication
+
+`mcp-server` использует workspace-scoped `platform API keys` как machine credentials.
+
+Контракт:
+
+- клиент передает `Authorization: Bearer crk_...`;
+- ключ должен принадлежать workspace из path;
+- `read` разрешает `initialize`, `notifications/initialized`, `ping`, `tools/list`;
+- `write` разрешает `tools/call`;
+- `deploy` сейчас включает те же MCP права, что и `write`, и зарезервирован для deploy-scoped automation;
+- успешная аутентификация обновляет `platform_api_keys.last_used_at`.
+
 ## 8. MCP lifecycle
 
 Поддерживаемые JSON-RPC методы: