feat(skills): preview installer plan during install

src/cli/skills.ts

@@ -2,7 +2,7 @@ import type { Command } from 'commander';
 import { resolve } from 'path';
 import { homedir } from 'os';
 import type { Skill } from '../skills/index.js';
-import { loadAllSkills, SkillInstaller, buildInstallerPlan } from '../skills/index.js';
+import { loadAllSkills, SkillInstaller, buildInstallerPlan, loadSkill } from '../skills/index.js';
 import { loadConfigSafe } from './shared.js';
 
 export interface SkillListRow {
@@ -30,6 +30,14 @@ export interface SkillInstallerPlanView {
   skipped: Array<{ installerType: string; reason: string }>;
 }
 
+export interface SkillInstallPreflightView {
+  sourcePath: string;
+  skill: SkillInstallerPlanView['skill'];
+  mode: 'dry-run';
+  steps: SkillInstallerPlanView['steps'];
+  skipped: SkillInstallerPlanView['skipped'];
+}
+
 export function toSkillListRows(skills: Skill[]): SkillListRow[] {
   return skills
     .map((skill) => ({
@@ -147,6 +155,47 @@ export function renderSkillInstallerPlan(view: SkillInstallerPlanView): string {
   return lines.join('\n');
 }
 
+export function toSkillInstallPreflightView(sourcePath: string): SkillInstallPreflightView | null {
+  const sourceSkill = loadSkill(resolve(sourcePath), 'managed');
+  if (!sourceSkill) {
+    return null;
+  }
+
+  const planView = toSkillInstallerPlanView(sourceSkill);
+  return {
+    sourcePath: resolve(sourcePath),
+    skill: planView.skill,
+    mode: planView.mode,
+    steps: planView.steps,
+    skipped: planView.skipped,
+  };
+}
+
+export function renderSkillInstallPreflight(view: SkillInstallPreflightView): string {
+  const lines: string[] = [
+    `Install preflight for '${view.skill.name}' from ${view.sourcePath}`,
+    `Mode: ${view.mode}`,
+  ];
+
+  if (view.steps.length === 0) {
+    lines.push('Planned installer steps: none');
+  } else {
+    lines.push('Planned installer steps:');
+    for (const step of view.steps) {
+      lines.push(`- [${step.installerType}] ${step.command}`);
+    }
+  }
+
+  if (view.skipped.length > 0) {
+    lines.push('Skipped installer steps:');
+    for (const skip of view.skipped) {
+      lines.push(`- [${skip.installerType}] ${skip.reason}`);
+    }
+  }
+
+  return lines.join('\n');
+}
+
 export function summarizeSkillsRefresh(skills: Skill[]): SkillRefreshSummary {
   const summary: SkillRefreshSummary = {
     total: skills.length,
@@ -290,8 +339,9 @@ export function registerSkillsCommand(program: Command): void {
   skills
     .command('install <path>')
     .description('Install a skill from a local directory')
+    .option('--json', 'Output preflight and install result as JSON')
     .option('-c, --config <path>', 'Config file path')
-    .action((pathArg: string, opts: { config?: string }) => {
+    .action((pathArg: string, opts: { json?: boolean; config?: string }) => {
       const loaded = loadConfigSafe(opts.config);
       if (loaded.error || !loaded.config) {
         console.error(loaded.error ?? 'Failed to load config');
@@ -301,6 +351,16 @@ export function registerSkillsCommand(program: Command): void {
 
       const defaultManagedDir = resolve(homedir(), '.flynn/workspace/skills');
       const installer = new SkillInstaller(loaded.config.skills.managed_dir ?? defaultManagedDir);
+      const preflight = toSkillInstallPreflightView(pathArg);
+
+      if (preflight) {
+        if (opts.json) {
+          console.log(JSON.stringify({ preflight }, null, 2));
+        } else {
+          console.log(renderSkillInstallPreflight(preflight));
+        }
+      }
+
       const result = installSkillFromDirectory(installer, pathArg);
 
       if (result.error || !result.skill) {
@@ -309,6 +369,24 @@ export function registerSkillsCommand(program: Command): void {
         return;
       }
 
+      if (opts.json) {
+        console.log(
+          JSON.stringify(
+            {
+              installed: {
+                name: result.skill.manifest.name,
+                version: result.skill.manifest.version,
+                tier: result.skill.manifest.tier,
+                directory: result.skill.directory,
+              },
+            },
+            null,
+            2,
+          ),
+        );
+        return;
+      }
+
       console.log(`Installed skill '${result.skill.manifest.name}' (${result.skill.manifest.version}).`);
     });