diff --git a/package-lock.json b/package-lock.json
index c434192c..36d62149 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1604,6 +1604,7 @@
 			"dependencies": {
 				"@anthropic-ai/sdk": "0.60.0",
 				"@google/genai": "1.14.0",
+				"chalk": "^5.5.0",
 				"openai": "5.12.2"
 			},
 			"devDependencies": {},
diff --git a/packages/ai/package.json b/packages/ai/package.json
index ce3f2273..7af2e7a0 100644
--- a/packages/ai/package.json
+++ b/packages/ai/package.json
@@ -15,7 +15,8 @@
 	"dependencies": {
 		"openai": "5.12.2",
 		"@anthropic-ai/sdk": "0.60.0",
-		"@google/genai": "1.14.0"
+		"@google/genai": "1.14.0",
+		"chalk": "^5.5.0"
 	},
 	"devDependencies": {},
 	"keywords": ["ai", "llm", "openai", "anthropic", "gemini", "unified", "api"],
diff --git a/packages/ai/src/providers/anthropic.ts b/packages/ai/src/providers/anthropic.ts
new file mode 100644
index 00000000..d7d7b003
--- /dev/null
+++ b/packages/ai/src/providers/anthropic.ts
@@ -0,0 +1,246 @@
+import Anthropic from "@anthropic-ai/sdk";
+import type {
+	ContentBlockParam,
+	MessageCreateParamsStreaming,
+	MessageParam,
+	Tool,
+} from "@anthropic-ai/sdk/resources/messages.js";
+import type { AI, AssistantMessage, Event, Message, Request, StopReason, TokenUsage, ToolCall } from "../types.js";
+
+export interface AnthropicOptions {
+	thinking?: {
+		enabled: boolean;
+		budgetTokens?: number;
+	};
+	toolChoice?: "auto" | "any" | "none" | { type: "tool"; name: string };
+}
+
+export class AnthropicAI implements AI<AnthropicOptions> {
+	private client: Anthropic;
+	private model: string;
+
+	constructor(model: string, apiKey?: string, baseUrl?: string) {
+		if (!apiKey) {
+			if (!process.env.ANTHROPIC_API_KEY) {
+				throw new Error(
+					"Anthropic API key is required. Set ANTHROPIC_API_KEY environment variable or pass it as an argument.",
+				);
+			}
+			apiKey = process.env.ANTHROPIC_API_KEY;
+		}
+		this.client = new Anthropic({ apiKey, baseURL: baseUrl });
+		this.model = model;
+	}
+
+	async complete(request: Request, options?: AnthropicOptions): Promise<AssistantMessage> {
+		try {
+			const messages = this.convertMessages(request.messages);
+
+			const params: MessageCreateParamsStreaming = {
+				model: this.model,
+				messages,
+				max_tokens: request.maxTokens || 4096,
+				stream: true,
+			};
+
+			if (request.systemPrompt) {
+				params.system = request.systemPrompt;
+			}
+
+			if (request.temperature !== undefined) {
+				params.temperature = request.temperature;
+			}
+
+			if (request.tools) {
+				params.tools = this.convertTools(request.tools);
+			}
+
+			if (options?.thinking?.enabled) {
+				params.thinking = {
+					type: "enabled",
+					budget_tokens: options.thinking.budgetTokens || 1024,
+				};
+			}
+
+			if (options?.toolChoice) {
+				if (typeof options.toolChoice === "string") {
+					params.tool_choice = { type: options.toolChoice };
+				} else {
+					params.tool_choice = options.toolChoice;
+				}
+			}
+
+			const stream = this.client.messages.stream(
+				{
+					...params,
+					stream: true,
+				},
+				{
+					signal: request.signal,
+				},
+			);
+
+			for await (const event of stream) {
+				if (event.type === "content_block_delta") {
+					if (event.delta.type === "text_delta") {
+						request.onText?.(event.delta.text);
+					}
+					if (event.delta.type === "thinking_delta") {
+						request.onThinking?.(event.delta.thinking);
+					}
+				}
+			}
+			const msg = await stream.finalMessage();
+			const thinking = msg.content.some((block) => block.type === "thinking")
+				? msg.content
+						.filter((block) => block.type === "thinking")
+						.map((block) => block.thinking)
+						.join("\n")
+				: undefined;
+			// This is kinda wrong if there is more than one thinking block. We do not use interleaved thinking though, so we should
+			// always have a single thinking block.
+			const thinkingSignature = msg.content.some((block) => block.type === "thinking")
+				? msg.content
+						.filter((block) => block.type === "thinking")
+						.map((block) => block.signature)
+						.join("\n")
+				: undefined;
+			const content = msg.content.some((block) => block.type === "text")
+				? msg.content
+						.filter((block) => block.type === "text")
+						.map((block) => block.text)
+						.join("\n")
+				: undefined;
+			const toolCalls: ToolCall[] = msg.content
+				.filter((block) => block.type === "tool_use")
+				.map((block) => ({
+					id: block.id,
+					name: block.name,
+					arguments: block.input as Record<string, any>,
+				}));
+			const usage: TokenUsage = {
+				input: msg.usage.input_tokens,
+				output: msg.usage.output_tokens,
+				cacheRead: msg.usage.cache_read_input_tokens || 0,
+				cacheWrite: msg.usage.cache_creation_input_tokens || 0,
+				// TODO add cost
+			};
+
+			return {
+				role: "assistant",
+				content,
+				thinking,
+				thinkingSignature,
+				toolCalls,
+				model: this.model,
+				usage,
+				stopResaon: this.mapStopReason(msg.stop_reason),
+			};
+		} catch (error) {
+			return {
+				role: "assistant",
+				model: this.model,
+				usage: {
+					input: 0,
+					output: 0,
+					cacheRead: 0,
+					cacheWrite: 0,
+				},
+				stopResaon: "error",
+				error: error instanceof Error ? error.message : String(error),
+			};
+		}
+	}
+
+	private convertMessages(messages: Message[]): MessageParam[] {
+		const params: MessageParam[] = [];
+
+		for (const msg of messages) {
+			if (msg.role === "user") {
+				params.push({
+					role: "user",
+					content: msg.content,
+				});
+			} else if (msg.role === "assistant") {
+				const blocks: ContentBlockParam[] = [];
+
+				if (msg.thinking && msg.thinkingSignature) {
+					blocks.push({
+						type: "thinking",
+						thinking: msg.thinking,
+						signature: msg.thinkingSignature,
+					});
+				}
+
+				if (msg.content) {
+					blocks.push({
+						type: "text",
+						text: msg.content,
+					});
+				}
+
+				if (msg.toolCalls) {
+					for (const toolCall of msg.toolCalls) {
+						blocks.push({
+							type: "tool_use",
+							id: toolCall.id,
+							name: toolCall.name,
+							input: toolCall.arguments,
+						});
+					}
+				}
+
+				params.push({
+					role: "assistant",
+					content: blocks,
+				});
+			} else if (msg.role === "toolResult") {
+				params.push({
+					role: "user",
+					content: [
+						{
+							type: "tool_result",
+							tool_use_id: msg.toolCallId,
+							content: msg.content,
+							is_error: msg.isError,
+						},
+					],
+				});
+			}
+		}
+		return params;
+	}
+
+	private convertTools(tools: Request["tools"]): Tool[] {
+		if (!tools) return [];
+
+		return tools.map((tool) => ({
+			name: tool.name,
+			description: tool.description,
+			input_schema: {
+				type: "object" as const,
+				properties: tool.parameters.properties || {},
+				required: tool.parameters.required || [],
+			},
+		}));
+	}
+
+	private mapStopReason(reason: Anthropic.Messages.StopReason | null): StopReason {
+		switch (reason) {
+			case "end_turn":
+				return "stop";
+			case "max_tokens":
+				return "length";
+			case "tool_use":
+				return "toolUse";
+			case "refusal":
+				return "safety";
+			case "pause_turn": // Stop is good enough -> resubmit
+				return "stop";
+			case "stop_sequence":
+				return "stop"; // We don't supply stop sequences, so this should never happen
+			default:
+				return "stop";
+		}
+	}
+}
diff --git a/packages/ai/src/types.ts b/packages/ai/src/types.ts
new file mode 100644
index 00000000..2eaf8eed
--- /dev/null
+++ b/packages/ai/src/types.ts
@@ -0,0 +1,105 @@
+export interface AI<T = any> {
+	complete(request: Request, options?: T): Promise<AssistantMessage>;
+}
+
+export interface ModelInfo {
+	id: string;
+	name: string;
+	provider: string;
+	capabilities: {
+		reasoning: boolean;
+		toolCall: boolean;
+		vision: boolean;
+		audio?: boolean;
+	};
+	cost: {
+		input: number; // per million tokens
+		output: number; // per million tokens
+		cacheRead?: number;
+		cacheWrite?: number;
+	};
+	limits: {
+		context: number;
+		output: number;
+	};
+	knowledge?: string;
+}
+
+export interface UserMessage {
+	role: "user";
+	content: string;
+}
+
+export interface AssistantMessage {
+	role: "assistant";
+	thinking?: string;
+	thinkingSignature?: string; // Leaky abstraction: needed for Anthropic
+	content?: string;
+	toolCalls?: {
+		id: string;
+		name: string;
+		arguments: Record<string, any>;
+	}[];
+	model: string;
+	usage: TokenUsage;
+
+	stopResaon: StopReason;
+	error?: string | Error;
+}
+
+export interface ToolResultMessage {
+	role: "toolResult";
+	content: string;
+	toolCallId: string;
+	isError: boolean;
+}
+
+export type Message = UserMessage | AssistantMessage | ToolResultMessage;
+
+export interface Tool {
+	name: string;
+	description: string;
+	parameters: Record<string, any>; // JSON Schema
+}
+
+export interface Request {
+	systemPrompt?: string;
+	messages: Message[];
+	tools?: Tool[];
+	temperature?: number;
+	maxTokens?: number;
+	onText?: (text: string) => void;
+	onThinking?: (thinking: string) => void;
+	signal?: AbortSignal;
+}
+
+export type Event =
+	| { type: "start"; model: string; provider: string }
+	| { type: "text"; content: string; delta: string }
+	| { type: "thinking"; content: string; delta: string }
+	| { type: "toolCall"; toolCall: ToolCall }
+	| { type: "usage"; usage: TokenUsage }
+	| { type: "done"; reason: StopReason; message: AssistantMessage }
+	| { type: "error"; error: Error };
+
+export interface ToolCall {
+	id: string;
+	name: string;
+	arguments: Record<string, any>;
+}
+
+export interface TokenUsage {
+	input: number;
+	output: number;
+	cacheRead: number;
+	cacheWrite: number;
+	cost?: {
+		input: number;
+		output: number;
+		cacheRead: number;
+		cacheWrite: number;
+		total: number;
+	};
+}
+
+export type StopReason = "stop" | "length" | "toolUse" | "safety" | "error";
diff --git a/packages/ai/test/examples/anthropic.ts b/packages/ai/test/examples/anthropic.ts
new file mode 100644
index 00000000..d6c0d66b
--- /dev/null
+++ b/packages/ai/test/examples/anthropic.ts
@@ -0,0 +1,63 @@
+import Anthropic from "@anthropic-ai/sdk";
+import { MessageCreateParamsBase } from "@anthropic-ai/sdk/resources/messages.mjs";
+import chalk from "chalk";
+import { AnthropicAI } from "../../src/providers/anthropic";
+import { Request, Message, Tool } from "../../src/types";
+
+const anthropic = new Anthropic();
+
+// Define a simple calculator tool
+const tools: Tool[] = [
+    {
+        name: "calculate",
+        description: "Perform a mathematical calculation",
+        parameters: {
+            type: "object" as const,
+            properties: {
+                expression: {
+                    type: "string",
+                    description: "The mathematical expression to evaluate"
+                }
+            },
+            required: ["expression"]
+        }
+    }
+];
+
+const ai = new AnthropicAI("claude-sonnet-4-0");
+const context: Request = {
+        messages: [
+        {
+            role: "user",
+            content: "Think about birds briefly. Then give me a list of 10 birds. Finally, calculate 42 * 17 + 123 and 453 + 434 in parallel using the calculator tool.",
+        }
+    ],
+    tools,
+    onText: (t) => process.stdout.write(t),
+    onThinking: (t) => process.stdout.write(chalk.dim(t))
+}
+
+const options = {thinking: { enabled: true }};
+let msg = await ai.complete(context, options)
+context.messages.push(msg);
+console.log(JSON.stringify(msg, null, 2));
+
+for (const toolCall of msg.toolCalls || []) {
+    if (toolCall.name === "calculate") {
+        const expression = toolCall.arguments.expression;
+        const result = eval(expression);
+        context.messages.push({
+            role: "toolResult",
+            content: `The result of ${expression} is ${result}.`,
+            toolCallId: toolCall.id,
+            isError: false
+        });
+    }
+}
+
+msg = await ai.complete(context, options);
+console.log(JSON.stringify(msg, null, 2));
+
+
+
+
diff --git a/todos/work/20250817-202050-ai-implementation-plan/analysis.md b/todos/work/20250817-202050-ai-implementation-plan/analysis.md
new file mode 100644
index 00000000..4c1053f6
--- /dev/null
+++ b/todos/work/20250817-202050-ai-implementation-plan/analysis.md
@@ -0,0 +1,140 @@
+# AI Package Implementation Analysis
+
+## Overview
+Based on the comprehensive plan in `packages/ai/plan.md` and detailed API documentation for OpenAI, Anthropic, and Gemini SDKs, the AI package needs to provide a unified API that abstracts over these three providers while maintaining their unique capabilities.
+
+## Existing Codebase Context
+
+### Current Structure
+- Monorepo using npm workspaces with packages in `packages/` directory
+- Existing packages: `tui`, `agent`, `pods`
+- TypeScript/ESM modules with Node.js ≥20.0.0
+- Biome for linting and formatting
+- Lockstep versioning at 0.5.8
+
+### Package Location
+The AI package should be created at `packages/ai/` following the existing pattern.
+
+## Key Implementation Requirements
+
+### Core Features
+1. **Unified Client API** - Single interface for all providers
+2. **Streaming First** - All providers support streaming, non-streaming is collected events
+3. **Provider Adapters** - OpenAI, Anthropic, Gemini adapters
+4. **Event Normalization** - Consistent event types across providers
+5. **Tool/Function Calling** - Unified interface for tools across providers
+6. **Thinking/Reasoning** - Support for reasoning models (o1/o3, Claude thinking, Gemini thinking)
+7. **Token Tracking** - Usage and cost calculation
+8. **Abort Support** - Request cancellation via AbortController
+9. **Error Mapping** - Normalized error handling
+10. **Caching** - Automatic caching strategies per provider
+
+### Provider-Specific Handling
+
+#### OpenAI
+- Dual APIs: Chat Completions vs Responses API
+- Responses API for o1/o3 reasoning content
+- Developer role for o1/o3 system prompts
+- Stream options for token usage
+
+#### Anthropic  
+- Content blocks always arrays
+- Separate system parameter
+- Tool results as user messages
+- Explicit thinking budget allocation
+- Cache control per block
+
+#### Gemini
+- Parts-based content system
+- Separate systemInstruction parameter
+- Model role instead of assistant
+- Thinking via part.thought flag
+- Function calls in parts array
+
+## Implementation Structure
+
+```
+packages/ai/
+├── src/
+│   ├── index.ts           # Main exports
+│   ├── types.ts           # Unified type definitions
+│   ├── client.ts          # Main AI client class
+│   ├── adapters/
+│   │   ├── base.ts        # Base adapter interface
+│   │   ├── openai.ts      # OpenAI adapter
+│   │   ├── anthropic.ts   # Anthropic adapter
+│   │   └── gemini.ts      # Gemini adapter
+│   ├── models/
+│   │   ├── models.ts      # Model info lookup
+│   │   └── models-data.ts # Generated models database
+│   ├── errors.ts          # Error mapping
+│   ├── events.ts          # Event stream handling
+│   ├── costs.ts           # Cost tracking
+│   └── utils.ts           # Utility functions
+├── test/
+│   ├── openai.test.ts
+│   ├── anthropic.test.ts
+│   └── gemini.test.ts
+├── scripts/
+│   └── update-models.ts   # Update models database
+├── package.json
+├── tsconfig.build.json
+└── README.md
+```
+
+## Dependencies
+- `openai`: ^5.12.2 (for OpenAI SDK)
+- `@anthropic-ai/sdk`: Latest
+- `@google/genai`: Latest
+
+## Files to Create/Modify
+
+### New Files in packages/ai/
+1. `package.json` - Package configuration
+2. `tsconfig.build.json` - TypeScript build config
+3. `src/index.ts` - Main exports
+4. `src/types.ts` - Type definitions
+5. `src/client.ts` - Main AI class
+6. `src/adapters/base.ts` - Base adapter
+7. `src/adapters/openai.ts` - OpenAI implementation
+8. `src/adapters/anthropic.ts` - Anthropic implementation
+9. `src/adapters/gemini.ts` - Gemini implementation
+10. `src/models/models.ts` - Model info
+11. `src/errors.ts` - Error handling
+12. `src/events.ts` - Event streaming
+13. `src/costs.ts` - Cost tracking
+14. `README.md` - Package documentation
+
+### Files to Modify
+1. Root `tsconfig.json` - Add path mapping for @mariozechner/pi-ai
+2. Root `package.json` - Add to build script order
+
+## Implementation Strategy
+
+### Phase 1: Core Structure
+- Create package structure and configuration
+- Define unified types and interfaces
+- Implement base adapter interface
+
+### Phase 2: Provider Adapters
+- Implement OpenAI adapter (both APIs)
+- Implement Anthropic adapter
+- Implement Gemini adapter
+
+### Phase 3: Features
+- Add streaming support
+- Implement tool calling
+- Add thinking/reasoning support
+- Implement token tracking
+
+### Phase 4: Polish
+- Error mapping and handling
+- Cost calculation
+- Model information database
+- Documentation and examples
+
+## Testing Approach
+- Unit tests for each adapter
+- Integration tests with mock responses
+- Example scripts for manual testing
+- Verify streaming, tools, thinking for each provider
\ No newline at end of file
diff --git a/todos/work/20250817-202050-ai-implementation-plan/task.md b/todos/work/20250817-202050-ai-implementation-plan/task.md
new file mode 100644
index 00000000..d00e9e59
--- /dev/null
+++ b/todos/work/20250817-202050-ai-implementation-plan/task.md
@@ -0,0 +1,40 @@
+# AI Package Implementation Plan
+**Status:** InProgress
+**Agent PID:** 5114
+
+## Original Todo
+ai: create an implementation plan based on packages/ai/plan.md and implement it
+
+## Description
+Implement the unified AI API as designed in packages/ai/plan.md. Create a single interface that works with OpenAI, Anthropic, and Gemini SDKs, handling their differences internally while exposing unified streaming events, tool calling, thinking/reasoning, and caching capabilities.
+
+*Read [plan.md](packages/ai/plan.md) in full for the complete API design and implementation details*
+
+## Implementation Plan
+- [x] Define unified types in src/types.ts based on plan.md interfaces (AIConfig, Message, Request, Event, TokenUsage, ModelInfo)
+- [ ] Implement OpenAI provider in src/providers/openai.ts with both Chat Completions and Responses API support
+- [x] Implement Anthropic provider in src/providers/anthropic.ts with MessageStream and content blocks handling
+- [ ] Implement Gemini provider in src/providers/gemini.ts with parts system and thinking extraction
+- [ ] Create main AI class in src/index.ts that selects and uses appropriate adapter
+- [ ] Implement models database in src/models.ts with model information and cost data
+- [ ] Add cost calculation integrated into each adapter's token tracking
+- [ ] Create comprehensive test suite in test/ai.test.ts using Node.js test framework
+- [ ] Test: Model database lookup and capabilities detection
+- [ ] Test: Basic completion (non-streaming) for all providers (OpenAI, Anthropic, Gemini, OpenRouter, Groq)
+- [ ] Test: Streaming responses with event normalization across all providers
+- [ ] Test: Thinking/reasoning extraction (o1 via Responses API, Claude thinking, Gemini thinking)
+- [ ] Test: Tool calling flow with execution and continuation across providers
+- [ ] Test: Automatic caching (Anthropic explicit, OpenAI/Gemini automatic)
+- [ ] Test: Message serialization/deserialization with full conversation history
+- [ ] Test: Cross-provider conversation continuation (start with one provider, continue with another)
+- [ ] Test: Abort/cancellation via AbortController
+- [ ] Test: Error handling and retry logic for each provider
+- [ ] Test: Cost tracking accuracy with known token counts
+- [ ] Update root tsconfig.json paths to include @mariozechner/pi-ai
+- [ ] Update root package.json build script to include AI package
+
+## Notes
+- Package structure already exists at packages/ai with dependencies installed
+- Each adapter handles its own event normalization internally
+- Tests use Node.js built-in test framework as per project conventions
+- Available API keys: OPENAI_API_KEY, ANTHROPIC_API_KEY, GEMINI_API_KEY, GROQ_API_KEY, OPENROUTER_API_KEY
\ No newline at end of file