feat: enable permission-aware subagents

pi-subagents/src/agent-types.ts

@@ -0,0 +1,346 @@
+/**
+ * agent-types.ts — Unified agent type registry.
+ *
+ * Merges embedded default agents with user-defined agents from .pi/agents/*.md, .agents/agents/*.md, and global agents.
+ * User agents override defaults with the same name. Disabled agents are kept but excluded from spawning.
+ */
+
+import { createCodingTools, createReadOnlyTools } from "@earendil-works/pi-coding-agent";
+import { DEFAULT_AGENTS } from "./default-agents.js";
+import type { AgentConfig } from "./types.js";
+
+/**
+ * All known built-in tool names, derived from pi's own tool factories rather
+ * than hardcoded so the set tracks pi-mono if it adds/renames a built-in.
+ * `createCodingTools` → read/bash/edit/write; `createReadOnlyTools` →
+ * read/grep/find/ls; their de-duplicated union is the 7 built-ins
+ * (read, bash, edit, write, grep, find, ls). The `cwd` only binds tool
+ * operations we never invoke here — we read each tool's `.name` and discard it.
+ */
+export const BUILTIN_TOOL_NAMES: string[] = [
+  ...new Set([...createCodingTools("."), ...createReadOnlyTools(".")].map((t) => t.name)),
+];
+
+/** Unified runtime registry of all agents (defaults + user-defined). */
+const agents = new Map<string, AgentConfig>();
+
+/** When true, DEFAULT_AGENTS are skipped during registration. */
+let disableDefaults = false;
+
+/** Check whether default agents are disabled. */
+export function isDefaultsDisabled(): boolean { return disableDefaults; }
+
+/** Set whether default agents are disabled. */
+export function setDefaultsDisabled(b: boolean): void { disableDefaults = b; }
+
+/** `fallbackSubagent` value that disables the fallback entirely (strict dispatch). */
+export const NO_FALLBACK = "none";
+
+/**
+ * Agent type substituted when a caller-supplied `subagent_type` doesn't resolve
+ * to exactly one enabled agent. `undefined` keeps the historical behavior
+ * (general-purpose); `NO_FALLBACK` makes dispatch fail closed. Set from
+ * `subagents.json` (`fallbackSubagent`).
+ *
+ * Module state rather than an index.ts closure because every caller-supplied
+ * spawn path needs it — the Agent tool, the scheduler, and cross-extension RPC.
+ */
+let fallbackSubagent: string | undefined;
+
+/** Get the configured fallback agent type. undefined = general-purpose. */
+export function getFallbackSubagent(): string | undefined { return fallbackSubagent; }
+
+/** Set the configured fallback agent type. undefined = general-purpose. */
+export function setFallbackSubagent(v: string | undefined): void { fallbackSubagent = v; }
+
+/**
+ * Build a registry map: DEFAULT_AGENTS first (unless disabled via settings),
+ * then user agents overlaid on top (same name overrides the default).
+ * Pure — callers that must not disturb the process-wide registry (nested
+ * delegation resolving agents from its own config root) build their own map.
+ */
+export function buildAgentRegistry(userAgents: Map<string, AgentConfig>): Map<string, AgentConfig> {
+  const registry = new Map<string, AgentConfig>();
+  if (!disableDefaults) {
+    for (const [name, config] of DEFAULT_AGENTS) registry.set(name, config);
+  }
+  for (const [name, config] of userAgents) registry.set(name, config);
+  return registry;
+}
+
+/**
+ * Register agents into the unified registry.
+ * Starts with DEFAULT_AGENTS, then overlays user agents (overrides defaults with same name).
+ * Disabled agents (enabled === false) are kept in the registry but excluded from spawning.
+ */
+export function registerAgents(userAgents: Map<string, AgentConfig>): void {
+  agents.clear();
+  for (const [name, config] of buildAgentRegistry(userAgents)) {
+    agents.set(name, config);
+  }
+}
+
+/** Case-insensitive key resolution within a registry. */
+function resolveKeyIn(registry: Map<string, AgentConfig>, name: string): string | undefined {
+  if (registry.has(name)) return name;
+  const lower = name.toLowerCase();
+  for (const key of registry.keys()) {
+    if (key.toLowerCase() === lower) return key;
+  }
+  return undefined;
+}
+
+/** Case-insensitive key resolution. */
+function resolveKey(name: string): string | undefined {
+  return resolveKeyIn(agents, name);
+}
+
+/** Resolve a type name case-insensitively in a registry. Returns the canonical key or undefined. */
+export function resolveTypeIn(registry: Map<string, AgentConfig>, name: string): string | undefined {
+  return resolveKeyIn(registry, name);
+}
+
+/** Get the agent config for a type (case-insensitive) from a registry. */
+export function getAgentConfigIn(registry: Map<string, AgentConfig>, name: string): AgentConfig | undefined {
+  const key = resolveKeyIn(registry, name);
+  return key ? registry.get(key) : undefined;
+}
+
+/** Check if a type is valid and enabled (case-insensitive) in a registry. */
+export function isValidTypeIn(registry: Map<string, AgentConfig>, type: string): boolean {
+  const key = resolveKeyIn(registry, type);
+  if (!key) return false;
+  return registry.get(key)?.enabled !== false;
+}
+
+/** Get all enabled type names in a registry (for spawning and tool descriptions). */
+export function getAvailableTypesIn(registry: Map<string, AgentConfig>): string[] {
+  return [...registry.entries()]
+    .filter(([_, config]) => config.enabled !== false)
+    .map(([name]) => name);
+}
+
+/**
+ * Case-insensitive resolution that refuses to guess. An exact match always wins;
+ * otherwise the name must match exactly one key. Two agents differing only in
+ * case are reachable (`loadCustomAgents` keys by filename across three
+ * directories), and picking whichever came first would silently dispatch a
+ * different agent, model and tool policy than the caller meant.
+ */
+function resolveUnambiguousKeyIn(registry: Map<string, AgentConfig>, name: string): string | undefined {
+  if (registry.has(name)) return name;
+  const lower = name.toLowerCase();
+  const matches = [...registry.keys()].filter(key => key.toLowerCase() === lower);
+  return matches.length === 1 ? matches[0] : undefined;
+}
+
+/**
+ * The canonical key for a caller-supplied name that identifies exactly one
+ * ENABLED agent, or undefined. Strict by construction: no fallback, no guessing
+ * between case-variants. Nested delegation resolves with this directly, since
+ * "unknown types are rejected rather than falling back" is its own contract.
+ */
+export function resolveEnabledTypeIn(
+  registry: Map<string, AgentConfig>,
+  requested: unknown,
+): string | undefined {
+  const raw = typeof requested === "string" ? requested.trim() : "";
+  if (!raw) return undefined;
+  const key = resolveUnambiguousKeyIn(registry, raw);
+  return key !== undefined && registry.get(key)?.enabled !== false ? key : undefined;
+}
+
+/** Outcome of resolving a caller-supplied `subagent_type` into a spawnable type. */
+export type SpawnTypeResolution =
+  /** Spawn this type. `fellBackFrom` is set when it isn't what the caller asked for. */
+  | { ok: true; type: string; fellBackFrom?: string }
+  /** Refuse the spawn and return this message to the caller. */
+  | { ok: false; message: string };
+
+/**
+ * Resolve a caller-supplied agent type against a registry, applying the
+ * `fallbackSubagent` policy. The single decision point for every caller-supplied
+ * spawn — the Agent tool, the scheduler, cross-extension RPC, and the nested
+ * tools — so a type that fails here never reaches `runAgent`, where `getConfig`
+ * would silently substitute general-purpose.
+ *
+ * Unknown, disabled, and case-ambiguous names are all treated the same way:
+ * the caller named something that doesn't identify exactly one enabled agent.
+ *
+ * Pure over `registry` — callers that need fresh agent files reload before
+ * calling (the Agent tool already does, per spawn). Reloading here would mean
+ * importing custom-agents.ts, which imports this module.
+ */
+export function resolveSpawnTypeIn(
+  registry: Map<string, AgentConfig>,
+  requested: unknown,
+): SpawnTypeResolution {
+  const raw = typeof requested === "string" ? requested.trim() : "";
+  const available = () => getAvailableTypesIn(registry).join(", ") || "(none)";
+
+  const key = resolveEnabledTypeIn(registry, raw);
+  if (key !== undefined) return { ok: true, type: key };
+
+  // A missing type follows the same policy as a wrong one rather than always
+  // erroring: before this setting existed an empty type fell back like any
+  // other unresolvable name, and only opting in should change that.
+  const reason = raw ? `Unknown or disabled agent type: "${raw}".` : "No agent type given.";
+
+  // Trimmed like `requested`: a padded value set programmatically would
+  // otherwise be reported as a missing agent.
+  const configured = typeof fallbackSubagent === "string" ? fallbackSubagent.trim() : undefined;
+
+  if (configured !== undefined && configured.toLowerCase() === NO_FALLBACK) {
+    return { ok: false, message: `${reason} Available: ${available()}.` };
+  }
+
+  if (configured !== undefined) {
+    // An explicitly configured fallback that is itself unusable is a
+    // misconfiguration, not a second chance to guess — say so rather than
+    // quietly dropping to general-purpose.
+    const fallbackKey = resolveUnambiguousKeyIn(registry, configured);
+    if (fallbackKey === undefined || registry.get(fallbackKey)?.enabled === false) {
+      return {
+        ok: false,
+        message:
+          `${reason} The configured fallbackSubagent "${configured}" is itself ` +
+          `unknown or disabled. Available: ${available()}.`,
+      };
+    }
+    return { ok: true, type: fallbackKey, fellBackFrom: raw };
+  }
+
+  // Unset: historical behavior, deliberately unchanged. #183 asks for the
+  // fallback to remain the default, so the pre-existing hole it leaves — an
+  // unregistered general-purpose resolving to `getConfig`'s all-tools hardcoded
+  // tier — is what `fallbackSubagent: none` is for, not something to close
+  // under everyone silently.
+  return { ok: true, type: "general-purpose", fellBackFrom: raw };
+}
+
+/** Resolve a caller-supplied agent type against the process-wide registry. */
+export function resolveSpawnType(requested: unknown): SpawnTypeResolution {
+  return resolveSpawnTypeIn(agents, requested);
+}
+
+/** Resolve a type name case-insensitively. Returns the canonical key or undefined. */
+export function resolveType(name: string): string | undefined {
+  return resolveKey(name);
+}
+
+/** Get the agent config for a type (case-insensitive). */
+export function getAgentConfig(name: string): AgentConfig | undefined {
+  return getAgentConfigIn(agents, name);
+}
+
+/** Get all enabled type names (for spawning and tool descriptions). */
+export function getAvailableTypes(): string[] {
+  return getAvailableTypesIn(agents);
+}
+
+/** Get all type names including disabled (for UI listing). */
+export function getAllTypes(): string[] {
+  return [...agents.keys()];
+}
+
+/** Get names of default agents currently in the registry. */
+export function getDefaultAgentNames(): string[] {
+  return [...agents.entries()]
+    .filter(([_, config]) => config.isDefault === true)
+    .map(([name]) => name);
+}
+
+/** Get names of user-defined agents (non-defaults) currently in the registry. */
+export function getUserAgentNames(): string[] {
+  return [...agents.entries()]
+    .filter(([_, config]) => config.isDefault !== true)
+    .map(([name]) => name);
+}
+
+/** Check if a type is valid and enabled (case-insensitive). */
+export function isValidType(type: string): boolean {
+  return isValidTypeIn(agents, type);
+}
+
+/** Tool names required for memory management. */
+const MEMORY_TOOL_NAMES = ["read", "write", "edit"];
+
+/**
+ * Get memory tool names (read/write/edit) not already in the provided set.
+ */
+export function getMemoryToolNames(existingToolNames: Set<string>): string[] {
+  return MEMORY_TOOL_NAMES.filter(n => !existingToolNames.has(n));
+}
+
+/** Tool names needed for read-only memory access. */
+const READONLY_MEMORY_TOOL_NAMES = ["read"];
+
+/**
+ * Get read-only memory tool names not already in the provided set.
+ */
+export function getReadOnlyMemoryToolNames(existingToolNames: Set<string>): string[] {
+  return READONLY_MEMORY_TOOL_NAMES.filter(n => !existingToolNames.has(n));
+}
+
+/** Get built-in tool names for a type (case-insensitive). */
+export function getToolNamesForType(type: string): string[] {
+  const key = resolveKey(type);
+  const raw = key ? agents.get(key) : undefined;
+  const config = raw?.enabled !== false ? raw : undefined;
+  // `undefined` (definition omitted the field) → all built-ins; an explicit `[]`
+  // (`tools: none` or a `tools:` with only `ext:` entries) → zero built-ins.
+  return config?.builtinToolNames ?? [...BUILTIN_TOOL_NAMES];
+}
+
+/** Get config for a type (case-insensitive, returns a SubagentTypeConfig-compatible object). Falls back to general-purpose. */
+export function getConfig(type: string): {
+  displayName: string;
+  color?: string;
+  description: string;
+  builtinToolNames: string[];
+  extensions: true | string[] | false;
+  excludeExtensions?: string[];
+  skills: true | string[] | false;
+  promptMode: "replace" | "append";
+} {
+  const key = resolveKey(type);
+  const config = key ? agents.get(key) : undefined;
+  if (config && config.enabled !== false) {
+    return {
+      displayName: config.displayName ?? config.name,
+      color: config.color,
+      description: config.description,
+      builtinToolNames: config.builtinToolNames ?? BUILTIN_TOOL_NAMES,
+      extensions: config.extensions,
+      excludeExtensions: config.excludeExtensions,
+      skills: config.skills,
+      promptMode: config.promptMode,
+    };
+  }
+
+  // Fallback for unknown/disabled types — general-purpose config
+  const gp = agents.get("general-purpose");
+  if (gp && gp.enabled !== false) {
+    return {
+      displayName: gp.displayName ?? gp.name,
+      color: gp.color,
+      description: gp.description,
+      builtinToolNames: gp.builtinToolNames ?? BUILTIN_TOOL_NAMES,
+      extensions: gp.extensions,
+      excludeExtensions: gp.excludeExtensions,
+      skills: gp.skills,
+      promptMode: gp.promptMode,
+    };
+  }
+
+  // Absolute fallback (should never happen)
+  return {
+    displayName: "Agent",
+    description: "General-purpose agent for complex, multi-step tasks",
+    builtinToolNames: BUILTIN_TOOL_NAMES,
+    extensions: true,
+    skills: true,
+    promptMode: "append",
+  };
+}
+