diff --git a/src/features/team-mode/member-guidance.ts b/src/features/team-mode/member-guidance.ts
new file mode 100644
index 000000000..e8849dfb6
--- /dev/null
+++ b/src/features/team-mode/member-guidance.ts
@@ -0,0 +1,25 @@
+import type { TeamModeConfig } from "../../config/schema/team-mode"
+
+export function buildTeammateCommunicationAddendum(_config: TeamModeConfig): string {
+  return `
+# Team Communication
+
+You are running as a team member. Your text responses are NOT visible to other team members or the lead.
+
+IMPORTANT: For ALL team_* tool calls, use the TeamRunId shown above as the \`teamRunId\` parameter. Do NOT use the team name.
+
+Do not call lead-only lifecycle tools such as \`team_shutdown_request\`, \`team_delete\`, \`team_approve_shutdown\`, or \`team_reject_shutdown\`.
+
+Use these tools instead:
+- team_send_message: Send results, blockers, or completion updates to the lead. Use \`to: "lead"\` for the lead, \`to: "<name>"\` for a specific member. Include \`summary\` and \`references\` when they help the lead triage quickly.
+- team_task_update: Update your task status. Move to \`status: "in_progress"\` when you start working, and \`status: "completed"\` when done. \`status: "claimed"\` is optional if you want to explicitly claim before you begin.
+- team_task_list: See all team tasks and their status.
+- team_task_get: Get details of a specific task.
+- delegate-task: Use this for bounded side work when needed.
+
+When you finish your assigned work, ALWAYS:
+1. Send your results to lead via team_send_message
+2. Mark your task as completed via team_task_update
+3. Send a completion message to lead so the lead can decide whether to request shutdown
+`
+}
diff --git a/src/features/team-mode/member-parser.ts b/src/features/team-mode/member-parser.ts
new file mode 100644
index 000000000..3e4914a9a
--- /dev/null
+++ b/src/features/team-mode/member-parser.ts
@@ -0,0 +1,82 @@
+export class MemberValidationError extends Error {
+  constructor(
+    message: string,
+    public readonly memberName?: string,
+    public readonly issue?: string,
+  ) {
+    super(message)
+    this.name = "MemberValidationError"
+  }
+}
+
+function translateMemberError(
+  input: Record<string, unknown>,
+  agentEligibilityRegistry: Readonly<Record<string, { verdict: "eligible" | "conditional" | "hard-reject"; rejectionMessage?: string }>>,
+): MemberValidationError {
+  const name = typeof input.name === "string" ? input.name : "<unnamed>"
+  const hasCategory = input.category != null
+  const hasSubagentType = input.subagent_type != null
+  const hasKind = input.kind === "category" || input.kind === "subagent_type"
+
+  if (hasCategory && hasSubagentType) {
+    return new MemberValidationError(
+      `Member '${name}' specifies both 'category' and 'subagent_type'. Must specify exactly one via 'kind' discriminator.`,
+      name,
+      "both-kinds",
+    )
+  }
+
+  if (!hasKind && !hasCategory && !hasSubagentType) {
+    return new MemberValidationError(
+      `Member '${name}' missing 'kind' discriminator. Specify either {kind:'category', category, prompt} or {kind:'subagent_type', subagent_type}.`,
+      name,
+      "missing-kind",
+    )
+  }
+
+  if (input.kind === "category" || (!hasKind && hasCategory)) {
+    const category = typeof input.category === "string" ? input.category : "<unknown>"
+    return new MemberValidationError(
+      `Member '${name}' uses category '${category}' but is missing required 'prompt' field. Category members must supply a task prompt.`,
+      name,
+      "category-missing-prompt",
+    )
+  }
+
+  if (input.kind === "subagent_type" || (!hasKind && hasSubagentType)) {
+    const subagentType = typeof input.subagent_type === "string" ? input.subagent_type : String(input.subagent_type)
+    if (typeof input.subagent_type !== "string" || !agentEligibilityRegistry[input.subagent_type]) {
+      return new MemberValidationError(
+        `Unknown subagent_type '${subagentType}'. Available ELIGIBLE agents: sisyphus, atlas, sisyphus-junior, hephaestus (if D-36 applied). Use delegate-task for read-only agents like oracle, librarian, explore, metis, momus, multimodal-looker.`,
+        name,
+        "unknown-subagent",
+      )
+    }
+  }
+
+  return new MemberValidationError(`Member '${name}' validation failed.`, name, "zod-residual")
+}
+
+export function createParseMember<TMember>(
+  memberSchema: { safeParse(input: unknown): { success: true; data: TMember } | { success: false } },
+  agentEligibilityRegistry: Readonly<Record<string, { verdict: "eligible" | "conditional" | "hard-reject"; rejectionMessage?: string }>>,
+): (input: unknown) => TMember {
+  return function parseMember(input: unknown) {
+    if (input == null || typeof input !== "object") {
+      throw new MemberValidationError("Member must be an object")
+    }
+
+    const raw = input as Record<string, unknown>
+    const result = memberSchema.safeParse(
+      raw.kind === undefined && (raw.category !== undefined || raw.subagent_type !== undefined)
+        ? { ...raw, kind: raw.category !== undefined ? "category" : "subagent_type" }
+        : raw,
+    )
+
+    if (!result.success) {
+      throw translateMemberError(raw, agentEligibilityRegistry)
+    }
+
+    return result.data
+  }
+}