diff --git a/packages/tool-bailian-kb/src/tools.ts b/packages/tool-bailian-kb/src/tools.ts
new file mode 100644
index 0000000..01f2d64
--- /dev/null
+++ b/packages/tool-bailian-kb/src/tools.ts
@@ -0,0 +1,237 @@
+/**
+ * The three model-facing knowledge tools. Schemas are static per deployment: a configured
+ * defaultAgentId downgrades agent_id to optional at build time (never a runtime fallback chain).
+ */
+
+import { defineTool } from '@deepseek-ai/dsh-tools'
+import type { SearchRequest, SearchResponse } from './api-types.js'
+import { KbApiError, type KbClient } from './client.js'
+import { consumeChatStream } from './chat.js'
+import { KB_PATHS } from './endpoints.js'
+import { listServices } from './services.js'
+
+/** Client-side chunk cap applied when the model omits top_k. */
+const DEFAULT_TOP_K = 5
+
+export interface KbToolDeps {
+  client: KbClient
+  defaultAgentId?: string
+  chatTimeoutMs: number
+}
+
+/** Format one service list into the error-hint / result text form. */
+function formatServices(services: { agent_id: string; name: string; scene: string; status: string }[]): string {
+  return services.map(s => `${s.agent_id} (${s.name}, scene=${s.scene}, ${s.status})`).join('; ')
+}
+
+/**
+ * Append the current service list to a client error so the model can correct
+ * an invalid agent_id in one step. Auth failures (401/403) keep their own message.
+ * @param client - the shared knowledge API client used for best-effort discovery.
+ * @param err - the failure being enriched; always rethrown.
+ * @returns never; the original or enriched error is thrown.
+ */
+async function withServiceHint(client: KbClient, err: unknown): Promise<never> {
+  if (err instanceof KbApiError && err.status !== undefined && err.status >= 400 && err.status !== 401 && err.status !== 403) {
+    let hint: string | undefined
+    try {
+      const { services } = await listServices(client, {})
+      if (services.length > 0) hint = formatServices(services)
+    } catch { /* discovery is best-effort; the original error already carries the failure */ }
+    if (hint !== undefined) throw new KbApiError(`${err.message}. Available services: ${hint}`, err.status)
+  }
+  throw err
+}
+
+/**
+ * Build the three tool definitions over one shared client.
+ * @param deps - client plus the deployment's explicit pinning and timeout choices.
+ * @returns definitions ready for `ctx.tools.register()`.
+ */
+export function createKbTools(deps: KbToolDeps) {
+  const { client, defaultAgentId, chatTimeoutMs } = deps
+  const agentIdParam = {
+    type: 'string' as const,
+    ...(defaultAgentId === undefined ? { required: true as const } : {}),
+    description: defaultAgentId === undefined
+      ? 'Retrieval/Q&A service id (find one via kb_service_list).'
+      : 'Retrieval/Q&A service id; omit to use this deployment\'s default service.',
+  }
+  const resolveAgentId = (supplied: string | undefined): string => {
+    const agentId = supplied ?? defaultAgentId
+    if (agentId === undefined) throw new Error('agent_id is required: discover services with kb_service_list')
+    return agentId
+  }
+
+  const serviceList = defineTool({
+    name: 'kb_service_list',
+    description:
+      'List the Bailian knowledge retrieval/Q&A services available in this workspace. '
+      + 'Each entry names the service id (agent_id) to pass to kb_search (scene=search) or kb_chat (scene=chat), '
+      + 'its bound knowledge bases, and its status (prefer deployed). '
+      + 'Omit scene to see both kinds; narrow large workspaces with name_filter.',
+    parameters: {
+      scene: { type: 'string', enum: ['chat', 'search'], description: 'Only list services for this scene; omitted lists both.' },
+      name_filter: { type: 'string', description: 'Fuzzy match on the service name.' },
+    },
+    output: {
+      schema: {
+        type: 'object',
+        additionalProperties: false,
+        properties: {
+          services: {
+            type: 'array',
+            required: true,
+            items: {
+              type: 'object',
+              additionalProperties: false,
+              properties: {
+                agent_id: { type: 'string', required: true },
+                name: { type: 'string', required: true },
+                scene: { type: 'string', required: true },
+                status: { type: 'string', required: true },
+                knowledge_bases: { type: 'array', required: true, items: { type: 'string' } },
+              },
+            },
+          },
+          total: { type: 'integer', required: true },
+          truncated: { type: 'boolean', required: true },
+        },
+      },
+      render: (_args, value) => [{
+        type: 'text',
+        text: value.services.length === 0
+          ? 'No knowledge services found.'
+          : `${value.services.length} service(s): ${formatServices(value.services)}`
+          + (value.truncated ? ` — listed first ${value.services.length} of ${value.total}; narrow with name_filter.` : ''),
+      }],
+    },
+    async execute(args) {
+      return await listServices(client, {
+        ...(args.scene === 'chat' || args.scene === 'search' ? { scene: args.scene } : {}),
+        ...(args.name_filter ? { nameFilter: args.name_filter } : {}),
+      })
+    },
+    presentCall: args => ({ card: 'generic', title: 'List knowledge services', kind: 'other', rawInput: args }),
+  })
+
+  const search = defineTool({
+    name: 'kb_search',
+    description:
+      'Semantic search over a Bailian knowledge base. Returns raw knowledge chunks with scores and source '
+      + 'references for you to verify, cite, or combine with other context. Retrieval scope and strategy '
+      + '(multi-KB weighting, routing, reranking) come from the service configuration. '
+      + 'top_k caps how many chunks return (client-side cut of the score-ranked results). '
+      + 'Use kb_chat instead when the user question can be answered by the knowledge base alone.',
+    parameters: {
+      query: { type: 'string', required: true, description: 'Search query text.' },
+      agent_id: agentIdParam,
+      top_k: { type: 'integer', description: `Maximum chunks to return; defaults to ${DEFAULT_TOP_K}.` },
+      images: { type: 'array', items: { type: 'string' }, description: 'Image URLs for multimodal retrieval.' },
+    },
+    output: {
+      schema: {
+        type: 'object',
+        additionalProperties: false,
+        properties: {
+          chunks: {
+            type: 'array',
+            required: true,
+            items: {
+              type: 'object',
+              additionalProperties: false,
+              properties: {
+                text: { type: 'string', required: true },
+                score: { type: 'number', required: true },
+                doc_name: { type: 'string' },
+                doc_id: { type: 'string' },
+                title: { type: 'string' },
+              },
+            },
+          },
+          total: { type: 'integer', required: true },
+        },
+      },
+      render: (_args, value) => [{
+        type: 'text',
+        text: value.chunks.length === 0
+          ? 'No matching knowledge chunks.'
+          : value.chunks.map((c, i) => `[${i + 1}] (score ${c.score.toFixed(2)}${c.doc_name ? `, ${c.doc_name}` : ''}) ${c.text}`).join('\n'),
+      }],
+    },
+    async execute(args) {
+      const topK = args.top_k ?? DEFAULT_TOP_K
+      const body: SearchRequest = {
+        query: args.query,
+        agent_id: resolveAgentId(args.agent_id),
+        ...(client.agentVersion ? { agent_version: client.agentVersion } : {}),
+        ...(args.images && args.images.length > 0 ? { images: args.images } : {}),
+      }
+      const res = await client.postJson<SearchResponse>(KB_PATHS.search, body).catch(err => withServiceHint(client, err))
+      const nodes = (res.data?.nodes ?? []).slice(0, topK)
+      return {
+        chunks: nodes.map(n => ({
+          text: n.text,
+          score: n.score,
+          ...(typeof n.metadata?.doc_name === 'string' ? { doc_name: n.metadata.doc_name } : {}),
+          ...(typeof n.metadata?.doc_id === 'string' ? { doc_id: n.metadata.doc_id } : {}),
+          ...(typeof n.metadata?.title === 'string' ? { title: n.metadata.title } : {}),
+        })),
+        total: res.data?.total ?? nodes.length,
+      }
+    },
+    presentCall: args => ({ card: 'generic', title: 'Search knowledge base', kind: 'search', rawInput: args }),
+  })
+
+  const chat = defineTool({
+    name: 'kb_chat',
+    description:
+      'Ask the knowledge base directly and get a complete, domain-tuned answer from a specialized RAG pipeline '
+      + '(multi-round retrieval + reranking + grounded generation). For knowledge Q&A this typically outperforms '
+      + 'searching and synthesizing yourself when the question can be answered by the knowledge base alone; '
+      + 'use kb_search instead when you need raw chunks to verify, cite, or combine with other work. '
+      + 'The pipeline runs an internal analysis/retrieval loop and may take a few minutes.',
+    parameters: {
+      message: { type: 'string', required: true, description: 'The question to ask.' },
+      agent_id: agentIdParam,
+    },
+    output: {
+      schema: {
+        type: 'object',
+        additionalProperties: false,
+        properties: {
+          answer: { type: 'string', required: true },
+          request_id: { type: 'string' },
+        },
+      },
+      render: (_args, value) => [{ type: 'text', text: value.answer.length === 0 ? '(empty answer)' : value.answer }],
+    },
+    async execute(args) {
+      const body = {
+        input: { messages: [{ role: 'user' as const, content: args.message }] },
+        parameters: { agent_options: {
+          agent_id: resolveAgentId(args.agent_id),
+          ...(client.agentVersion ? { agent_version: client.agentVersion } : {}),
+        } },
+        stream: true as const,
+      }
+      let res: Response
+      try {
+        res = await client.postSse(KB_PATHS.chat, body, AbortSignal.timeout(chatTimeoutMs))
+      } catch (err) {
+        if (err instanceof Error && err.name === 'TimeoutError') {
+          throw new Error(
+            `knowledge chat timed out after ${chatTimeoutMs}ms; the pipeline runs a multi-round retrieval loop `
+            + 'and long questions can exceed the deployment timeout. Retry, or use kb_search for raw chunks instead.',
+          )
+        }
+        return await withServiceHint(client, err)
+      }
+      const { answer, requestId } = await consumeChatStream(res)
+      return { answer, ...(requestId ? { request_id: requestId } : {}) }
+    },
+    presentCall: args => ({ card: 'generic', title: 'Ask knowledge base (may take a few minutes)', kind: 'fetch', rawInput: args }),
+  })
+
+  return [serviceList, search, chat]
+}
diff --git a/packages/tool-bailian-kb/tests/tools.test.ts b/packages/tool-bailian-kb/tests/tools.test.ts
new file mode 100644
index 0000000..1ac7d1f
--- /dev/null
+++ b/packages/tool-bailian-kb/tests/tools.test.ts
@@ -0,0 +1,81 @@
+import { describe, expect, it, vi } from 'vitest'
+import { KbApiError, KbClient } from '../src/client.js'
+import { createKbTools } from '../src/tools.js'
+
+const EXEC = {} as never
+
+function toolsWith(postJson: unknown, postSse?: unknown, defaultAgentId?: string) {
+  const client = { postJson, postSse, agentVersion: undefined } as unknown as KbClient
+  const list = createKbTools({ client, ...(defaultAgentId ? { defaultAgentId } : {}), chatTimeoutMs: 1000 })
+  const byName = Object.fromEntries(list.map(t => [t.name, t]))
+  return { byName, list }
+}
+
+const searchResponse = {
+  request_id: 'r1',
+  data: { total: 3, nodes: [
+    { score: 0.9, text: 'A', metadata: { doc_name: 'd1' } },
+    { score: 0.8, text: 'B', metadata: {} },
+    { score: 0.7, text: 'C', metadata: {} },
+  ] },
+}
+
+describe('createKbTools', () => {
+  it('registers exactly kb_service_list, kb_search, kb_chat', () => {
+    const { list } = toolsWith(vi.fn())
+    expect(list.map(t => t.name).sort()).toEqual(['kb_chat', 'kb_search', 'kb_service_list'])
+  })
+
+  it('kb_search truncates nodes client-side to top_k and never sends top_k to the server', async () => {
+    const postJson = vi.fn(async (_path: string, _body: unknown) => searchResponse)
+    const { byName } = toolsWith(postJson)
+    const out = await byName.kb_search!.execute({ query: 'q', agent_id: 'aid-1', top_k: 2 }, EXEC) as { chunks: unknown[] }
+    expect(out.chunks).toHaveLength(2)
+    const body = postJson.mock.calls[0]![1] as Record<string, unknown>
+    expect(body).not.toHaveProperty('top_k')
+    expect(body.agent_id).toBe('aid-1')
+  })
+
+  it('agent_id is required without defaultAgentId and optional with one', () => {
+    const withoutDefault = toolsWith(vi.fn()).byName.kb_search!
+    const withDefault = toolsWith(vi.fn(), undefined, 'aid-fixed').byName.kb_search!
+    // defineTool compiles the spec into JSON Schema: requiredness lives in the top-level `required` array.
+    const requiredList = (tool: { parameters: Record<string, unknown> }) =>
+      (tool.parameters.required ?? []) as string[]
+    expect(requiredList(withoutDefault)).toContain('agent_id')
+    expect(requiredList(withDefault)).not.toContain('agent_id')
+  })
+
+  it('kb_search falls back to defaultAgentId as an explicit resolve step', async () => {
+    const postJson = vi.fn(async (_path: string, _body: unknown) => searchResponse)
+    const { byName } = toolsWith(postJson, undefined, 'aid-fixed')
+    await byName.kb_search!.execute({ query: 'q' }, EXEC)
+    expect((postJson.mock.calls[0]![1] as Record<string, unknown>).agent_id).toBe('aid-fixed')
+  })
+
+  it('a 4xx failure appends the current service list to the error', async () => {
+    const postJson = vi.fn(async (path: string) => {
+      if (path === '/api/v1/indices/knowledge/search') throw new KbApiError('agent not found', 400)
+      return { data: { total_count: 1, rows: [{ agent_id: 'aid-9', agent_name: 'faq', agent_scene: 'search', agent_status: 'deployed' }] } }
+    })
+    const { byName } = toolsWith(postJson)
+    const err = await byName.kb_search!.execute({ query: 'q', agent_id: 'bad' }, EXEC).catch((e: unknown) => e)
+    expect((err as Error).message).toContain('aid-9')
+  })
+
+  it('kb_chat buffers the SSE stream into one answer', async () => {
+    const sse = 'data: {"output":{"choices":[{"message":{"content":"hi"},"finish_reason":"stop"}]},"request_id":"r2"}\n\ndata: [DONE]\n\n'
+    const postSse = vi.fn(async () => new Response(sse, { status: 200 }))
+    const { byName } = toolsWith(vi.fn(), postSse)
+    const out = await byName.kb_chat!.execute({ message: 'q', agent_id: 'aid-1' }, EXEC) as { answer: string }
+    expect(out.answer).toBe('hi')
+  })
+
+  it('kb_chat translates a timeout into retry-or-search guidance', async () => {
+    const timeout = Object.assign(new Error('operation timed out'), { name: 'TimeoutError' })
+    const postSse = vi.fn(async () => { throw timeout })
+    const { byName } = toolsWith(vi.fn(), postSse)
+    const err = await byName.kb_chat!.execute({ message: 'q', agent_id: 'aid-1' }, EXEC).catch((e: unknown) => e)
+    expect((err as Error).message).toMatch(/timed out.*kb_search/s)
+  })
+})