feat(07-01): add optional council member filtering

- add optional members arg support to athena_council tool

- filter selected members case-insensitively with clear unknown-member errors

- add tests for default-all and member selection behavior

src/tools/athena-council/tools.test.ts

@@ -3,7 +3,7 @@
 import { describe, expect, test } from "bun:test"
 import type { BackgroundManager } from "../../features/background-agent"
 import { ATHENA_COUNCIL_TOOL_DESCRIPTION } from "./constants"
-import { createAthenaCouncilTool } from "./tools"
+import { createAthenaCouncilTool, filterCouncilMembers } from "./tools"
 
 const mockManager = {
   getTask: () => undefined,
@@ -19,6 +19,78 @@ const mockToolContext = {
   abort: new AbortController().signal,
 }
 
+const configuredMembers = [
+  { name: "Claude", model: "anthropic/claude-sonnet-4-5" },
+  { name: "GPT", model: "openai/gpt-5.3-codex" },
+  { model: "google/gemini-3-pro" },
+]
+
+describe("filterCouncilMembers", () => {
+  test("returns all members when selection is undefined", () => {
+    // #given
+    const selectedMembers = undefined
+
+    // #when
+    const result = filterCouncilMembers(configuredMembers, selectedMembers)
+
+    // #then
+    expect(result.members).toEqual(configuredMembers)
+    expect(result.error).toBeUndefined()
+  })
+
+  test("returns all members when selection is empty", () => {
+    // #given
+    const selectedMembers: string[] = []
+
+    // #when
+    const result = filterCouncilMembers(configuredMembers, selectedMembers)
+
+    // #then
+    expect(result.members).toEqual(configuredMembers)
+    expect(result.error).toBeUndefined()
+  })
+
+  test("filters members using case-insensitive name and model matching", () => {
+    // #given
+    const selectedMembers = ["gpt", "GOOGLE/GEMINI-3-PRO"]
+
+    // #when
+    const result = filterCouncilMembers(configuredMembers, selectedMembers)
+
+    // #then
+    expect(result.members).toEqual([configuredMembers[1], configuredMembers[2]])
+    expect(result.error).toBeUndefined()
+  })
+
+  test("returns helpful error when selected members are not configured", () => {
+    // #given
+    const selectedMembers = ["mistral", "xai/grok-3"]
+
+    // #when
+    const result = filterCouncilMembers(configuredMembers, selectedMembers)
+
+    // #then
+    expect(result.members).toEqual([])
+    expect(result.error).toBe(
+      "Unknown council members: mistral, xai/grok-3. Available members: Claude, GPT, google/gemini-3-pro."
+    )
+  })
+
+  test("returns error listing only unmatched names when partially matched", () => {
+    // #given
+    const selectedMembers = ["claude", "non-existent"]
+
+    // #when
+    const result = filterCouncilMembers(configuredMembers, selectedMembers)
+
+    // #then
+    expect(result.members).toEqual([])
+    expect(result.error).toBe(
+      "Unknown council members: non-existent. Available members: Claude, GPT, google/gemini-3-pro."
+    )
+  })
+})
+
 describe("createAthenaCouncilTool", () => {
   test("returns error when councilConfig is undefined", async () => {
     // #given
@@ -58,5 +130,24 @@ describe("createAthenaCouncilTool", () => {
     // #then
     expect(athenaCouncilTool.description).toBe(ATHENA_COUNCIL_TOOL_DESCRIPTION)
     expect((athenaCouncilTool as { args: Record<string, unknown> }).args.question).toBeDefined()
+    expect((athenaCouncilTool as { args: Record<string, unknown> }).args.members).toBeDefined()
+  })
+
+  test("returns helpful error when members contains invalid names", async () => {
+    // #given
+    const athenaCouncilTool = createAthenaCouncilTool({
+      backgroundManager: mockManager,
+      councilConfig: { members: configuredMembers },
+    })
+    const toolArgs = {
+      question: "Who should investigate this?",
+      members: ["unknown-model"],
+    }
+
+    // #when
+    const result = await athenaCouncilTool.execute(toolArgs, mockToolContext)
+
+    // #then
+    expect(result).toBe("Unknown council members: unknown-model. Available members: Claude, GPT, google/gemini-3-pro.")
   })
 })