feat(athena): add dedicated council-member agent for multi-model council

Replace oracle as the agent for council background tasks with a purpose-built

council-member agent. This avoids coupling to oracle's config/prompt and provides

proper read-only tool restrictions (deny write, edit, task, athena_council).

- New council-member-agent.ts with analysis-oriented system prompt

- Registered in agentSources (hidden from Sisyphus delegation table)

- Added to type system, Zod schemas, display names, tool restrictions

- Minimal model fallback (always overridden per council member at launch)

- Council orchestrator now launches members as council-member agent

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/agents/athena/council-member-agent.ts

@@ -0,0 +1,24 @@
+import type { AgentConfig } from "@opencode-ai/sdk"
+import type { AgentMode } from "../types"
+
+const MODE: AgentMode = "subagent"
+
+const COUNCIL_MEMBER_PROMPT = `You are an independent code analyst in a multi-model council. Your role is to provide thorough, evidence-based analysis of the question you receive.
+
+## Instructions
+- Search the codebase using available tools (Read, Grep, Glob, LSP)
+- Report findings with evidence: file paths, line numbers, code snippets
+- For each finding, state severity (critical/high/medium/low) and confidence (high/medium/low)
+- Focus on real issues backed by evidence, not hypothetical concerns
+- Be concise but thorough — quality over quantity`
+
+export function createCouncilMemberAgent(model: string): AgentConfig {
+  return {
+    description: "Independent code analyst for Athena multi-model council. Read-only, evidence-based analysis. (Council Member - OhMyOpenCode)",
+    mode: MODE,
+    model,
+    temperature: 0.1,
+    prompt: COUNCIL_MEMBER_PROMPT,
+  } as AgentConfig
+}
+createCouncilMemberAgent.mode = MODE

src/agents/athena/council-orchestrator.test.ts

@@ -65,7 +65,7 @@ describe("executeCouncil", () => {
 
     for (const launch of launches) {
       expect(launch.prompt).toBe(expectedPrompt)
-      expect(launch.agent).toBe("athena")
+      expect(launch.agent).toBe("council-member")
     }
 
     expect(launches[0]?.model).toEqual({ providerID: "openai", modelID: "gpt-5.3-codex" })

src/agents/athena/council-orchestrator.ts

@@ -75,7 +75,7 @@ async function launchMember(
   return launcher.launch({
     description: `Council member: ${memberName}`,
     prompt,
-    agent: "athena",
+    agent: "council-member",
     parentSessionID,
     parentMessageID,
     parentAgent,

src/agents/athena/index.ts

@@ -1,5 +1,6 @@
 export * from "./types"
 export * from "./agent"
+export * from "./council-member-agent"
 export * from "./model-parser"
 export * from "./council-prompt"
 export * from "./council-orchestrator"

src/agents/builtin-agents.ts

@@ -13,6 +13,7 @@ import { createAtlasAgent, atlasPromptMetadata } from "./atlas"
 import { createMomusAgent, momusPromptMetadata } from "./momus"
 import { createHephaestusAgent } from "./hephaestus"
 import { createAthenaAgent, ATHENA_PROMPT_METADATA } from "./athena/agent"
+import { createCouncilMemberAgent } from "./athena/council-member-agent"
 import type { AvailableCategory } from "./dynamic-agent-prompt-builder"
 import {
   fetchAvailableModels,
@@ -40,6 +41,7 @@ const agentSources: Partial<Record<BuiltinAgentName, AgentSource>> = {
   metis: createMetisAgent,
   momus: createMomusAgent,
   athena: createAthenaAgent,
+  "council-member": createCouncilMemberAgent,
   // Note: Atlas is handled specially in createBuiltinAgents()
   // because it needs OrchestratorContext, not just a model string
   atlas: createAtlasAgent as AgentFactory,

src/agents/types.ts

@@ -104,6 +104,7 @@ export type BuiltinAgentName =
   | "momus"
   | "atlas"
   | "athena"
+  | "council-member"
 
 export type OverridableAgentName =
   | "build"

src/config/schema/agent-names.ts

@@ -12,6 +12,7 @@ export const BuiltinAgentNameSchema = z.enum([
   "momus",
   "atlas",
   "athena",
+  "council-member",
 ])
 
 export const BuiltinSkillNameSchema = z.enum([
@@ -38,6 +39,7 @@ export const OverridableAgentNameSchema = z.enum([
   "multimodal-looker",
   "atlas",
   "athena",
+  "council-member",
 ])
 
 export const AgentNameSchema = BuiltinAgentNameSchema

src/shared/agent-display-names.ts

@@ -16,6 +16,7 @@ export const AGENT_DISPLAY_NAMES: Record<string, string> = {
   librarian: "librarian",
   explore: "explore",
   "multimodal-looker": "multimodal-looker",
+  "council-member": "council-member",
 }
 
 /**

src/shared/agent-tool-restrictions.ts

@@ -50,6 +50,14 @@ const AGENT_RESTRICTIONS: Record<string, Record<string, boolean>> = {
   },
 
   athena: ATHENA_RESTRICTIONS,
+
+  "council-member": {
+    write: false,
+    edit: false,
+    task: false,
+    call_omo_agent: false,
+    athena_council: false,
+  },
 }
 
 function permissionToToolBooleans(

src/shared/model-requirements.ts

@@ -100,6 +100,11 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
     ],
   },
+  "council-member": {
+    fallbackChain: [
+      { providers: ["opencode"], model: "gpt-5-nano" },
+    ],
+  },
 }
 
 export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {