diff --git a/tests/runner-e2e/chat-catalog-domains/external-slack-provider.test.ts b/tests/runner-e2e/chat-catalog-domains/external-slack-provider.test.ts
new file mode 100644
index 00000000000..bc5d24885c6
--- /dev/null
+++ b/tests/runner-e2e/chat-catalog-domains/external-slack-provider.test.ts
@@ -0,0 +1,28 @@
+import { describe,expect,it } from "vitest";
+import type { ChatConversation,ChatEndpoint,ExternalChannelBindingSummary } from "../../../packages/shared/src/types/chat-channels.js";
+import { assertSlackCall,assertSlackFixture,slackIngressMatches,type SlackIngressReceipt } from "./external-slack-provider.js";
+function binding(){return {disposable:true as const,resourceIds:["TWORKSPACE","CCHANNEL","USENDER","UBOT","AAPP"],credentialEnv:["PAPERCLIP_CHAT_EVAL_SLACK_BOT","PAPERCLIP_CHAT_EVAL_SLACK_SENDER","PAPERCLIP_CHAT_EVAL_SLACK_SIGNING","PAPERCLIP_CHAT_EVAL_SLACK_CONFIG"],prerequisites:{workspaceId:"TWORKSPACE",channelId:"CCHANNEL",senderUserId:"USENDER",botUserId:"UBOT",appId:"AAPP",registeredWebhookOrigin:"https://isolated.example.test",botTokenEnv:"PAPERCLIP_CHAT_EVAL_SLACK_BOT",senderTokenEnv:"PAPERCLIP_CHAT_EVAL_SLACK_SENDER",signingSecretEnv:"PAPERCLIP_CHAT_EVAL_SLACK_SIGNING",configurationTokenEnv:"PAPERCLIP_CHAT_EVAL_SLACK_CONFIG"}};}
+function ingress(){const receipt:SlackIngressReceipt={providerCalls:1,query:"Exact canonical query.",endpointId:"endpoint",conversationId:"conversation",issueId:"issue",humanCommentId:"comment",linkedPaperclipUserId:"human",provider:{workspaceId:"TWORKSPACE",channelId:"CCHANNEL",threadId:"1793050000.123456",canonicalMessageId:"1793050001.123456",senderUserId:"USENDER"}};return {receipt,endpoint:{id:"endpoint",companyId:"company",assignedAgentId:"ceo",provider:"slack",providerAccountId:"TWORKSPACE",botExternalId:"UBOT"} as ChatEndpoint,conversation:{id:"conversation",endpointId:"endpoint",companyId:"company",issueId:"issue",externalConversationId:"slack:CCHANNEL",externalThreadId:"slack:CCHANNEL:1793050000.123456"} as ChatConversation,binding:{endpointId:"endpoint",conversationId:"conversation",provider:"slack",assignedAgentLocked:true} as ExternalChannelBindingSummary,comment:{id:"comment",body:"Exact canonical query.",authorUserId:"human",metadata:{sourceChannel:"slack"}},canonicalQuery:"Exact canonical query.",companyId:"company",agentId:"ceo"};}
+describe("finite real Slack companion prerequisites and source binding",()=>{
+ it("requires each explicit disposable provider resource and a distinct actual human sender",()=>{
+  expect(()=>assertSlackFixture(binding())).not.toThrow();const other=binding();other.resourceIds=other.resourceIds.filter(id=>id!=="USENDER");expect(()=>assertSlackFixture(other)).toThrow(/allowlisted/);
+  const bot=binding();bot.prerequisites.senderUserId="UBOT";expect(()=>assertSlackFixture(bot)).toThrow(/real linked human/);
+ });
+ it("refuses arbitrary Slack methods, another app/channel and unscoped post requests",()=>{
+  expect(()=>assertSlackCall(binding(),"sender","chat.postMessage",{channel:"CCHANNEL",text:"Exact original query"})).not.toThrow();
+  for(const action of [()=>assertSlackCall(binding(),"sender","users.list",{}),()=>assertSlackCall(binding(),"sender","chat.postMessage",{channel:"COTHER"}),()=>assertSlackCall(binding(),"sender","chat.postMessage",{}),()=>assertSlackCall(binding(),"configuration","apps.manifest.update",{app_id:"AOTHER"})])expect(action).toThrow();
+ });
+ it("accepts exact canonical linked-human source identity across the actual public DTOs",()=>expect(slackIngressMatches(ingress())).toBe(true));
+ it("rejects copied company hints, wrong sender/comment, wrong thread, lost canonical bytes and missing dispatch",()=>{
+  for(const mutate of [
+   (i:ReturnType<typeof ingress>)=>{i.endpoint.companyId="another-company";},
+   (i:ReturnType<typeof ingress>)=>{i.receipt.provider.senderUserId="UBOT";},
+   (i:ReturnType<typeof ingress>)=>{i.comment.authorUserId="another-human";},
+   (i:ReturnType<typeof ingress>)=>{i.comment.body="A rewritten easier query.";},
+   (i:ReturnType<typeof ingress>)=>{i.conversation.externalThreadId="slack:CCHANNEL:1793050009.123456";},
+   (i:ReturnType<typeof ingress>)=>{i.conversation.externalConversationId="CCHANNEL";},
+   (i:ReturnType<typeof ingress>)=>{i.binding.conversationId="another-conversation";},
+   (i:ReturnType<typeof ingress>)=>{i.receipt.providerCalls=0;},
+  ]){const i=ingress();mutate(i);expect(slackIngressMatches(i)).toBe(false);}
+ });
+});
diff --git a/tests/runner-e2e/chat-catalog-domains/external-slack-provider.ts b/tests/runner-e2e/chat-catalog-domains/external-slack-provider.ts
new file mode 100644
index 00000000000..3c65dbe7207
--- /dev/null
+++ b/tests/runner-e2e/chat-catalog-domains/external-slack-provider.ts
@@ -0,0 +1,46 @@
+import type { ChatCatalogContext } from "../chat-catalog-contract.js";
+import type { ChatConversation,ChatEndpoint,ExternalChannelBindingSummary } from "../../../packages/shared/src/types/chat-channels.js";
+import { selectedExternalCredential,type ProviderBinding } from "./external-fixtures.js";
+
+export const slackCompanionFields=["workspaceId","channelId","senderUserId","botUserId","appId","registeredWebhookOrigin","botTokenEnv","senderTokenEnv","signingSecretEnv","configurationTokenEnv"] as const;
+const methods={bot:new Set(["auth.test","conversations.info","conversations.replies","conversations.history","chat.postMessage","files.info"]),sender:new Set(["auth.test","chat.postMessage","files.getUploadURLExternal","files.completeUploadExternal"]),configuration:new Set(["apps.manifest.export","apps.manifest.update"])};
+export function assertSlackFixture(binding:ProviderBinding){
+ const p=binding.prerequisites;
+ for(const field of slackCompanionFields)if(!p[field])throw new Error(`Setup blocker: Slack ${field} reference is required`);
+ for(const [field,pattern] of [["workspaceId",/^T[A-Z0-9]+$/],["channelId",/^[CG][A-Z0-9]+$/],["senderUserId",/^[UW][A-Z0-9]+$/],["botUserId",/^[UW][A-Z0-9]+$/],["appId",/^A[A-Z0-9]+$/]] as const){if(!pattern.test(p[field]!)||!binding.resourceIds.includes(p[field]!))throw new Error(`Setup blocker: Slack ${field} is not an explicitly allowlisted disposable provider resource`);}
+ const origin=new URL(p.registeredWebhookOrigin!);if(origin.protocol!=="https:"||origin.username||origin.password||origin.search||origin.hash||origin.pathname!=="/")throw new Error("Setup blocker: Slack requires an explicitly designated HTTPS webhook origin for this isolated attempt");
+ if(p.botUserId===p.senderUserId)throw new Error("Setup blocker: canonical Slack sender must be the real linked human, not the app bot");
+}
+export function assertSlackCall(binding:ProviderBinding,kind:keyof typeof methods,method:string,parameters:Record<string,unknown>){
+ assertSlackFixture(binding);if(!methods[kind].has(method))throw new Error("Slack fixture method exceeds its finite provider contract");
+ const p=binding.prerequisites;
+ if("channel" in parameters&&parameters.channel!==p.channelId)throw new Error("Slack fixture call escaped its allowed channel");
+ if("channel_id" in parameters&&parameters.channel_id!==p.channelId)throw new Error("Slack fixture upload escaped its allowed channel");
+ if("app_id" in parameters&&parameters.app_id!==p.appId)throw new Error("Slack fixture call escaped its allowed disposable app");
+ if((method==="apps.manifest.export"||method==="apps.manifest.update")&&parameters.app_id!==p.appId)throw new Error("Slack manifest operation requires the exact owned app");
+ if(method==="chat.postMessage"&&parameters.channel!==p.channelId)throw new Error("Slack canonical input requires the exact allowed channel");
+}
+/** Official Slack HTTP only. No fixture call occurs during import/calibration. */
+export function slackProvider(ctx:ChatCatalogContext,binding:ProviderBinding,fetcher:typeof fetch=fetch){
+ assertSlackFixture(binding);let calls=0;const receipts:Array<{kind:string;method:string;ok:boolean}>=[];
+ return {receipts,async call<T extends Record<string,unknown>>(kind:keyof typeof methods,method:string,parameters:Record<string,unknown>,signal?:AbortSignal):Promise<T>{
+  assertSlackCall(binding,kind,method,parameters);if(++calls>40)throw new Error("Slack fixture exceeded its declared bounded provider calls");
+  const token=selectedExternalCredential(ctx,binding,kind==="bot"?"botTokenEnv":kind==="sender"?"senderTokenEnv":"configurationTokenEnv");
+  const response=await fetcher(`https://slack.com/api/${method}`,{method:"POST",redirect:"error",signal:signal?AbortSignal.any([signal,AbortSignal.timeout(20000)]):AbortSignal.timeout(20000),headers:{authorization:`Bearer ${token}`,"content-type":"application/json; charset=utf-8"},body:JSON.stringify(parameters)});
+  if(!response.ok){receipts.push({kind,method,ok:false});await response.body?.cancel();throw new Error(`Slack fixture ${method} returned HTTP ${response.status}; private response withheld`);}
+  const bytes=Buffer.from(await response.arrayBuffer());if(bytes.length>2*1024*1024)throw new Error("Slack fixture response exceeds bounded metadata size");
+  let result:T;try{result=JSON.parse(bytes.toString("utf8")) as T;}catch{throw new Error("Slack fixture returned invalid metadata; response withheld");}
+  receipts.push({kind,method,ok:result.ok===true});if(result.ok!==true)throw new Error(`Slack fixture ${method} was not accepted; provider error details withheld`);return result;
+ }};
+}
+export interface SlackIngressReceipt {providerCalls:number;query:string;endpointId:string;conversationId:string;issueId:string;humanCommentId:string;linkedPaperclipUserId:string;provider:{workspaceId:string;channelId:string;threadId:string;canonicalMessageId:string;senderUserId:string}}
+/** Source-qualified public DTO checks; externalThreadId is the SDK encoded key. */
+export function slackIngressMatches(input:{receipt:SlackIngressReceipt;endpoint:ChatEndpoint;conversation:ChatConversation;binding:ExternalChannelBindingSummary;comment:{id:string;body:string;authorUserId:string|null;metadata?:{sourceChannel?:string}};canonicalQuery:string;companyId:string;agentId:string}){
+ const {receipt:r,endpoint:e,conversation:c,binding:b,comment}=input;
+ return Number.isSafeInteger(r.providerCalls)&&r.providerCalls>=1&&r.providerCalls<=20&&r.query===input.canonicalQuery&&e.id===r.endpointId&&e.companyId===input.companyId&&e.assignedAgentId===input.agentId&&e.provider==="slack"&&e.providerAccountId===r.provider.workspaceId
+  &&c.id===r.conversationId&&c.endpointId===e.id&&c.companyId===input.companyId&&c.issueId===r.issueId&&c.externalThreadId===`slack:${r.provider.channelId}:${r.provider.threadId}`
+  &&c.externalConversationId===`slack:${r.provider.channelId}`
+  &&b.endpointId===e.id&&b.conversationId===c.id&&b.provider==="slack"&&b.assignedAgentLocked===true
+  &&comment.id===r.humanCommentId&&comment.body===input.canonicalQuery&&comment.authorUserId===r.linkedPaperclipUserId&&comment.metadata?.sourceChannel==="slack"
+  &&/^\d+\.\d{6}$/.test(r.provider.threadId)&&/^\d+\.\d{6}$/.test(r.provider.canonicalMessageId)&&r.provider.senderUserId!==e.botExternalId;
+}