diff --git a/packages/core/src/agent.ts b/packages/core/src/agent.ts
index d6f65707..2dc9ff65 100644
--- a/packages/core/src/agent.ts
+++ b/packages/core/src/agent.ts
@@ -54,6 +54,7 @@ import { CognitivePreparation, selectCognitiveDepth } from './cognitive.js';
 import { detectEnvironment, type EnvironmentProfile } from './environment-profile.js';
 import { ToolSelector } from './tool-selector.js';
 import type { SkillRegistry } from './skills/types.js';
+import { findSkillsProvidingTool } from './skills/index.js';
 import { writeFileSync, readFileSync, existsSync, mkdirSync } from 'node:fs';
 import { join } from 'node:path';
 import { AsyncLocalStorage } from 'node:async_hooks';
@@ -5217,6 +5218,7 @@ export class Agent {
         category: s.category,
         hasInstructions: !!s.instructions,
         hasMcpTools: !!s.mcpServers && Object.keys(s.mcpServers).length > 0,
+        providesTools: s.providesTools,
       }));
       return JSON.stringify({
         status: 'ok',
@@ -5340,7 +5342,52 @@ export class Agent {
         }
       }
 
-      // 3. Not found as tool or skill
+      // 3. Check if a skill's providesTools includes this name (L2 progressive loading)
+      if (this.skillRegistry) {
+        const allManifests = this.skillRegistry.list();
+        const matchingSkills = findSkillsProvidingTool(allManifests, name);
+        if (matchingSkills.length > 0) {
+          // Try to auto-activate the first matching skill
+          const skillName = matchingSkills[0];
+          const skill = this.skillRegistry.get(skillName);
+          if (skill) {
+            let autoActivated = false;
+            if (skill.manifest.instructions) {
+              this.activatedSkillInstructions.set(skillName, skill.manifest.instructions);
+              autoActivated = true;
+            }
+            if (skill.manifest.mcpServers && this.skillMcpActivator) {
+              try {
+                const mcpTools = await this.skillMcpActivator(skillName, skill.manifest.mcpServers);
+                for (const tool of mcpTools) {
+                  this.registerTool(tool);
+                  this.activateTools([tool.name]);
+                }
+                if (mcpTools.length > 0) {
+                  autoActivated = true;
+                  skillToolNames.push(...mcpTools.map(t => t.name));
+                }
+              } catch (err) {
+                log.warn('Failed to auto-activate skill MCP servers for tool request', {
+                  agentId: this.id, skill: skillName, toolName: name, error: String(err),
+                });
+              }
+            }
+            if (autoActivated) {
+              activated.push(`${name} (auto-activated skill "${skillName}")`);
+              log.info('Tool auto-activated via skill providesTools', {
+                agentId: this.id, toolName: name, skillName,
+              });
+              continue;
+            }
+          }
+          // Skill found but couldn't auto-activate — add hint
+          unknown.push(name);
+          continue;
+        }
+      }
+
+      // 4. Not found as tool or skill
       unknown.push(name);
     }
 
@@ -5357,8 +5404,9 @@ export class Agent {
     }
     if (unknown.length > 0) {
       result.unknown = unknown;
-      result.hint = 'These names were not found as tools or skills. '
-        + 'Use discover_tools({ mode: "list_skills" }) to see all available skills.';
+      result.hint = 'These names were not found as activated tools or skills. '
+        + 'Use discover_tools({ mode: "list_skills" }) to see all available skills '
+        + 'and their provided tools.';
     }
     return JSON.stringify(result);
   }
diff --git a/packages/core/src/skills/index.ts b/packages/core/src/skills/index.ts
index 7096974e..25d81849 100644
--- a/packages/core/src/skills/index.ts
+++ b/packages/core/src/skills/index.ts
@@ -1,6 +1,18 @@
+/** Re-export types */
 export type { SkillManifest, SkillMcpServerConfig, SkillInstance, SkillRegistry, SkillCategory, SkillToolDef } from './types.js';
 export { InMemorySkillRegistry } from './registry.js';
 
+/**
+ * Search an array of SkillManifests for ones whose providesTools includes the given toolName.
+ * Returns the names of matching skills.
+ */
+export function findSkillsProvidingTool(manifests: SkillManifest[], toolName: string): string[] {
+  const lowerTool = toolName.toLowerCase();
+  return manifests
+    .filter(m => m.providesTools?.some(t => t.toLowerCase() === lowerTool))
+    .map(m => m.name);
+}
+
 import { homedir } from 'node:os';
 import { join } from 'node:path';
 import { existsSync, readFileSync, readdirSync, statSync } from 'node:fs';
@@ -101,6 +113,7 @@ export function discoverSkillsInDir(dir: string): Array<{ manifest: SkillManifes
         mcpServers: resolveMcpServerPaths(pkg.skill?.mcpServers, skillDir),
         isolation: pkg.skill?.isolation,
         alwaysOn: pkg.skill?.alwaysOn ?? undefined,
+        providesTools: pkg.skill?.providesTools,
         sourcePath: skillDir,
       };
       results.push({ manifest, path: skillDir, source: dir });
diff --git a/packages/core/src/skills/types.ts b/packages/core/src/skills/types.ts
index 97e78caa..7b1b8d7d 100644
--- a/packages/core/src/skills/types.ts
+++ b/packages/core/src/skills/types.ts
@@ -34,6 +34,13 @@ export interface SkillManifest {
   builtIn?: boolean;
   /** If true, full instructions are auto-injected into every agent (not just listed as available) */
   alwaysOn?: boolean;
+  /** Tool names this skill provides for L2 progressive loading.
+   *  When an agent requests a tool not found in the active tool set, the system
+   *  checks if any skill's providesTools includes that tool name. If so, it can
+   *  auto-activate the skill to make the tool available.
+   *  This avoids loading all skill MCP servers eagerly (L0) or loading all
+   *  skill instructions into context (L1). */
+  providesTools?: string[];
 }
 
 export type SkillCategory =
diff --git a/packages/core/test/skill-progressive-loading.test.ts b/packages/core/test/skill-progressive-loading.test.ts
new file mode 100644
index 00000000..5d71b4f7
--- /dev/null
+++ b/packages/core/test/skill-progressive-loading.test.ts
@@ -0,0 +1,235 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { InMemorySkillRegistry } from '../src/skills/registry.js';
+import { findSkillsProvidingTool } from '../src/skills/index.js';
+import type { SkillManifest, SkillInstance } from '../src/skills/types.js';
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+function makeSkillManifest(overrides: Partial<SkillManifest> & { name: string }): SkillManifest {
+  return {
+    name: overrides.name,
+    version: overrides.version ?? '1.0.0',
+    description: overrides.description ?? `Skill ${overrides.name}`,
+    author: overrides.author ?? 'test',
+    category: overrides.category ?? 'development',
+    tags: overrides.tags ?? [],
+    instructions: overrides.instructions,
+    mcpServers: overrides.mcpServers,
+    providesTools: overrides.providesTools,
+    builtIn: overrides.builtIn,
+    alwaysOn: overrides.alwaysOn,
+    sourcePath: overrides.sourcePath,
+  };
+}
+
+function makeSkillInstance(overrides: Partial<SkillManifest> & { name: string }): SkillInstance {
+  return { manifest: makeSkillManifest(overrides) };
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+describe('SkillManifest — providesTools field', () => {
+
+  it('can have a providesTools field with tool names', () => {
+    const manifest: SkillManifest = {
+      name: 'chrome-devtools',
+      version: '1.0.0',
+      description: 'Browser automation',
+      author: 'markus',
+      category: 'browser',
+      providesTools: ['browser_navigate', 'browser_click', 'browser_type'],
+    };
+    expect(manifest.providesTools).toBeDefined();
+    expect(manifest.providesTools!.length).toBe(3);
+    expect(manifest.providesTools!).toContain('browser_navigate');
+    expect(manifest.providesTools!).toContain('browser_click');
+    expect(manifest.providesTools!).toContain('browser_type');
+  });
+
+  it('is optional — SkillManifest without providesTools is valid', () => {
+    const manifest: SkillManifest = {
+      name: 'my-skill',
+      version: '1.0.0',
+      description: 'A skill without providesTools',
+      author: 'test',
+      category: 'custom',
+    };
+    expect(manifest.providesTools).toBeUndefined();
+  });
+
+  it('can be an empty array', () => {
+    const manifest: SkillManifest = {
+      name: 'empty-skill',
+      version: '1.0.0',
+      description: 'Skill with empty providesTools',
+      author: 'test',
+      category: 'custom',
+      providesTools: [],
+    };
+    expect(manifest.providesTools).toEqual([]);
+  });
+});
+
+describe('findSkillsProvidingTool', () => {
+
+  it('returns skill names when a match is found', () => {
+    const manifests: SkillManifest[] = [
+      makeSkillManifest({ name: 'chrome', providesTools: ['browser_navigate', 'browser_click'] }),
+      makeSkillManifest({ name: 'node', providesTools: ['shell_execute'] }),
+    ];
+    const result = findSkillsProvidingTool(manifests, 'browser_navigate');
+    expect(result).toEqual(['chrome']);
+  });
+
+  it('returns empty array when no skill provides the tool', () => {
+    const manifests: SkillManifest[] = [
+      makeSkillManifest({ name: 'chrome', providesTools: ['browser_navigate'] }),
+    ];
+    const result = findSkillsProvidingTool(manifests, 'unknown_tool');
+    expect(result).toEqual([]);
+  });
+
+  it('returns empty array when no skills have providesTools', () => {
+    const manifests: SkillManifest[] = [
+      makeSkillManifest({ name: 'plain-skill' }),
+    ];
+    const result = findSkillsProvidingTool(manifests, 'any_tool');
+    expect(result).toEqual([]);
+  });
+
+  it('returns empty array when manifests array is empty', () => {
+    const result = findSkillsProvidingTool([], 'any_tool');
+    expect(result).toEqual([]);
+  });
+
+  it('returns multiple skill names when multiple skills provide the same tool', () => {
+    const manifests: SkillManifest[] = [
+      makeSkillManifest({ name: 'skill-a', providesTools: ['shared_tool'] }),
+      makeSkillManifest({ name: 'skill-b', providesTools: ['shared_tool', 'other_tool'] }),
+      makeSkillManifest({ name: 'skill-c', providesTools: ['different_tool'] }),
+    ];
+    const result = findSkillsProvidingTool(manifests, 'shared_tool');
+    expect(result).toHaveLength(2);
+    expect(result).toContain('skill-a');
+    expect(result).toContain('skill-b');
+    expect(result).not.toContain('skill-c');
+  });
+
+  it('is case-insensitive (tool names are compared in lowercase)', () => {
+    const manifests: SkillManifest[] = [
+      makeSkillManifest({ name: 'skill', providesTools: ['Browser_Navigate'] }),
+    ];
+    // Both lowercase and mixed-case variants match because findSkillsProvidingTool
+    // normalizes both sides to lowercase
+    expect(findSkillsProvidingTool(manifests, 'browser_navigate')).toEqual(['skill']);
+    expect(findSkillsProvidingTool(manifests, 'Browser_Navigate')).toEqual(['skill']);
+    expect(findSkillsProvidingTool(manifests, 'BROWSER_NAVIGATE')).toEqual(['skill']);
+  });
+});
+
+describe('findSkillsProvidingTool with InMemorySkillRegistry', () => {
+
+  let registry: InMemorySkillRegistry;
+
+  beforeEach(() => {
+    registry = new InMemorySkillRegistry();
+    registry.register(makeSkillInstance({
+      name: 'chrome-devtools',
+      providesTools: ['browser_navigate', 'browser_click', 'browser_snapshot'],
+    }));
+    registry.register(makeSkillInstance({
+      name: 'shell-tools',
+      providesTools: ['shell_execute', 'shell_script'],
+    }));
+  });
+
+  it('finds tools across registered skills', () => {
+    const result = findSkillsProvidingTool(registry.list(), 'browser_navigate');
+    expect(result).toEqual(['chrome-devtools']);
+  });
+
+  it('returns empty when tool is not provided by any registered skill', () => {
+    const result = findSkillsProvidingTool(registry.list(), 'file_read');
+    expect(result).toEqual([]);
+  });
+
+  it('finds tool from second skill', () => {
+    const result = findSkillsProvidingTool(registry.list(), 'shell_execute');
+    expect(result).toEqual(['shell-tools']);
+  });
+});
+
+describe('SkillRegistry — providesTools stored and listed', () => {
+
+  it('stores providesTools when registering a skill', () => {
+    const registry = new InMemorySkillRegistry();
+    registry.register(makeSkillInstance({
+      name: 'test-skill',
+      providesTools: ['tool_a', 'tool_b'],
+    }));
+    const manifests = registry.list();
+    expect(manifests).toHaveLength(1);
+    expect(manifests[0]!.providesTools).toEqual(['tool_a', 'tool_b']);
+  });
+
+  it('includes providesTools in list() output', () => {
+    const registry = new InMemorySkillRegistry();
+    registry.register(makeSkillInstance({
+      name: 'skill-a',
+      providesTools: ['alpha'],
+    }));
+    registry.register(makeSkillInstance({
+      name: 'skill-b',
+      providesTools: ['beta'],
+    }));
+    registry.register(makeSkillInstance({
+      name: 'skill-c',
+      // no providesTools
+    }));
+    const manifests = registry.list();
+    const a = manifests.find(m => m.name === 'skill-a');
+    const b = manifests.find(m => m.name === 'skill-b');
+    const c = manifests.find(m => m.name === 'skill-c');
+    expect(a?.providesTools).toEqual(['alpha']);
+    expect(b?.providesTools).toEqual(['beta']);
+    expect(c?.providesTools).toBeUndefined();
+  });
+
+  it('survives unregister and re-register', () => {
+    const registry = new InMemorySkillRegistry();
+    const inst = makeSkillInstance({ name: 'temp', providesTools: ['temp_tool'] });
+    registry.register(inst);
+    expect(findSkillsProvidingTool(registry.list(), 'temp_tool')).toEqual(['temp']);
+
+    registry.unregister('temp');
+    expect(findSkillsProvidingTool(registry.list(), 'temp_tool')).toEqual([]);
+
+    registry.register(makeSkillInstance({ name: 'temp', providesTools: ['temp_tool'] }));
+    expect(findSkillsProvidingTool(registry.list(), 'temp_tool')).toEqual(['temp']);
+  });
+});
+
+describe('chrome-devtools skill.json — providesTools present', () => {
+
+  it('has the correct providesTools in the template', () => {
+    // This test validates that the chrome-devtools template skill.json
+    // includes providesTools for L2 progressive loading
+    const fs = require('node:fs');
+    const path = require('node:path');
+    const skillJsonPath = path.resolve(
+      __dirname, '..', '..', '..', 'templates', 'skills', 'chrome-devtools', 'skill.json',
+    );
+    const content = JSON.parse(fs.readFileSync(skillJsonPath, 'utf-8'));
+    expect(content.skill.providesTools).toBeDefined();
+    expect(Array.isArray(content.skill.providesTools)).toBe(true);
+    expect(content.skill.providesTools).toContain('browser_navigate');
+    expect(content.skill.providesTools).toContain('browser_snapshot');
+    expect(content.skill.providesTools).toContain('browser_click');
+    expect(content.skill.providesTools).toContain('browser_type');
+    expect(content.skill.providesTools).toContain('browser_evaluate');
+  });
+});
diff --git a/packages/shared/src/types/package.ts b/packages/shared/src/types/package.ts
index da5c68ba..009453f5 100644
--- a/packages/shared/src/types/package.ts
+++ b/packages/shared/src/types/package.ts
@@ -67,6 +67,11 @@ export interface SkillSection {
   isolation?: 'shared' | 'per-agent';
   /** If true, instructions are auto-injected into every agent (not just available for discovery) */
   alwaysOn?: boolean;
+  /** Tool names this skill provides for L2 progressive loading.
+   *  When an agent requests a tool not found in the active set, the system
+   *  checks if any skill's providesTools includes that tool name, and can
+   *  auto-activate the skill to fulfill the request. */
+  providesTools?: string[];
 }
 
 // ─── Top-level manifest ─────────────────────────────────────────────────────
@@ -195,6 +200,8 @@ export function buildManifest(
       requiredPermissions: (skillSection?.requiredPermissions ?? raw.requiredPermissions) as SkillSection['requiredPermissions'],
       mcpServers: (skillSection?.mcpServers ?? raw.mcpServers) as SkillSection['mcpServers'],
       isolation: (skillSection?.isolation ?? raw.isolation) as SkillSection['isolation'],
+      alwaysOn: (skillSection?.alwaysOn ?? raw.alwaysOn) as boolean | undefined,
+      providesTools: (skillSection?.providesTools ?? raw.providesTools) as string[] | undefined,
     };
     // Pull version/author from raw if present
     if (!base.version || base.version === '1.0.0') {
diff --git a/templates/skills/chrome-devtools/skill.json b/templates/skills/chrome-devtools/skill.json
index 23426787..37e917a2 100644
--- a/templates/skills/chrome-devtools/skill.json
+++ b/templates/skills/chrome-devtools/skill.json
@@ -17,6 +17,7 @@
     "skillFile": "SKILL.md",
     "requiredPermissions": ["browser", "network"],
     "isolation": "pooled",
+    "providesTools": ["browser_navigate", "browser_snapshot", "browser_click", "browser_type", "browser_evaluate"],
     "mcpServers": {
       "chrome-devtools": {
         "command": "npx",