Cline SDK Skill

Consolidated skill for building AI agents with the Cline SDK. Use the decision trees below to find the right entry point and API surface, then load detailed references.

Critical Rules

Follow these rules in all Cline SDK code:

1. Install with npm install @cline/sdk. The @cline/sdk package re-exports @cline/core, not every sub-package directly. Core re-exports the public SDK surface such as ClineCore, Agent, createAgentRuntime, createTool, built-in tool helpers, provider helpers, and the Llms namespace. Import from @cline/agents, @cline/llms, or @cline/shared only when you need APIs that core does not re-export, such as AgentRuntime, createAgent, or some low-level types.
2. Requires Node.js 22 or later.
3. Use createTool() from @cline/sdk (or @cline/shared) to define tools. Tool names must be snake_case.
4. Prefer returning structured error data from tool execute functions when the agent can recover. Direct Agent converts thrown tool errors into error tool results; ClineCore can also count repeated failed tool turns toward its mistake-limit handling.
5. Use lifecycle: { completesRun: true } on tools that should end the agent loop (e.g. a "submit answer" tool).
6. When using ClineCore, always call dispose() when done to clean up resources.
7. The direct Agent and ClineCore have different event systems. For Agent: use agent.subscribe() to get AgentRuntimeEvent types, text streaming is "assistant-text-delta", and result text is result.outputText. For ClineCore: use cline.subscribe() to get CoreSessionEvent types. Render user-facing text, reasoning, and tool activity from "agent_event" payloads (content_start, content_update, content_end, done). Treat "chunk" events as raw transport chunks with { stream, chunk, ts }, not as typed text deltas. ClineCore result text is result.text. There is no top-level onEvent field on AgentRuntimeConfig; use agent.subscribe() or hooks.onEvent instead. Do not use "content_update" or "content_start" with agent.subscribe(); those are host-facing AgentEvent types carried inside ClineCore agent_event events.
8. For direct Agent, plugins are simple runtime plugins with setup(context) returning { tools, hooks }. For ClineCore, extensions are AgentPlugin objects with manifest, setup(api, ctx), and optional hooks. Do not use ClineCore plugin examples inside direct Agent.plugins.
9. Plugin skills are file-based, not registered. There is no registerSkill() and no api.registerSkill. A plugin ships skills as SKILL.md files under <package>/skills/<name>/SKILL.md (package shape required); the host discovers them and surfaces them as /slash-commands automatically -- do not call registerCommand for skills. Plugin MCP servers use api.registerMcpServer() with the "mcp" capability. Configured agents (agent profiles) are YAML files in .cline/agents/ loaded as subagent_<name> tools when enableSpawnAgent is true.

How to Use This Skill

Reference File Structure

The two main API surfaces (Agent and ClineCore) follow a 4-file pattern. Cross-cutting concepts are single-file guides.

Each main API surface in ./references/<api>/ contains:

Cross-cutting concepts in ./references/<concept>/ have REFERENCE.md as the entry point.

Reading Order

1. Start with REFERENCE.md for your chosen API surface
2. Then read additional files relevant to your task:
   • Writing agent code -> api.md
   • Common patterns -> patterns.md
   • Creating tools -> tools/REFERENCE.md
   • Adding plugins/hooks -> plugins/REFERENCE.md
   • Configuring LLM providers -> providers/REFERENCE.md
   • Streaming events -> events/REFERENCE.md
   • Deploying to production -> production/REFERENCE.md
   • Scheduling agents -> scheduling/REFERENCE.md
   • Multi-agent orchestration -> multi-agent/REFERENCE.md
   • Debugging -> gotchas.md

Example Paths

./references/agent/REFERENCE.md           # Start here for lightweight agents
./references/clinecore/REFERENCE.md       # Start here for full runtime
./references/agent/api.md                 # Agent class, config, methods
./references/tools/REFERENCE.md           # Creating and using tools
./references/plugins/REFERENCE.md         # Plugin system
./references/providers/REFERENCE.md       # LLM provider configuration

Quick Decision Trees

"Which API surface should I use?"

Which API?
+-- I want a simple, in-memory agent with custom tools
|   +-- agent/ (Agent class from @cline/agents, re-exported by @cline/sdk)
+-- I need session persistence, built-in tools, config discovery
|   +-- clinecore/ (ClineCore from @cline/core)
+-- I want built-in file/shell/search/web tools
|   +-- clinecore/ (has built-in tools; Agent does not)
+-- I want scheduled or recurring agents
|   +-- clinecore/ (automation API)
+-- I need multi-process or multi-client session sharing
|   +-- clinecore/ (hub-backed runtime)
+-- I'm building a browser-compatible agent
|   +-- agent/ (no Node.js dependencies)

"I need to create tools"

Tools?
+-- Define a custom tool with schema -> tools/REFERENCE.md
+-- Use built-in tools (read_files, search_codebase, run_commands, etc.) -> tools/REFERENCE.md (built-in section)
+-- Control tool approval/policies -> tools/REFERENCE.md (policies section)
+-- Tool that ends the agent loop -> tools/REFERENCE.md (completion tools)
+-- Package tools as a reusable plugin -> plugins/REFERENCE.md

"I need to handle events"

Events?
+-- Stream text/reasoning in real time -> events/REFERENCE.md
+-- Track token usage and costs -> events/REFERENCE.md
+-- Watch tool calls -> events/REFERENCE.md
+-- Detect completion/errors -> events/REFERENCE.md
+-- Hook into lifecycle stages -> plugins/REFERENCE.md

"I need to configure a model provider"

Providers?
+-- Anthropic (Claude) -> providers/REFERENCE.md
+-- OpenAI (GPT) -> providers/REFERENCE.md
+-- Google (Gemini/Vertex) -> providers/REFERENCE.md
+-- AWS Bedrock -> providers/REFERENCE.md
+-- Mistral -> providers/REFERENCE.md
+-- OpenAI-compatible (vLLM, Together, etc.) -> providers/REFERENCE.md
+-- Custom/self-hosted provider -> providers/REFERENCE.md

"I need plugins or hooks"

Plugins?
+-- Package tools + hooks together -> plugins/REFERENCE.md
+-- Observe tool calls (logging, metrics) -> plugins/REFERENCE.md
+-- Intercept lifecycle events -> plugins/REFERENCE.md
+-- Add system prompt rules -> plugins/REFERENCE.md
+-- Expose an MCP server's tools -> plugins/REFERENCE.md (MCP servers)
+-- Bundle reusable skills (SKILL.md, auto slash commands) -> plugins/REFERENCE.md (bundled skills)
+-- Distribute via npm/git -> plugins/REFERENCE.md

"I need multi-agent coordination"

Multi-agent?
+-- Run one-off delegated sub-agents -> multi-agent/REFERENCE.md (sub-agents)
+-- Predefined named sub-agents from files -> multi-agent/REFERENCE.md (configured agents)
+-- Persistent cross-session teams -> multi-agent/REFERENCE.md (teams)
+-- Parent-child delegation -> multi-agent/REFERENCE.md (sub-agents)
+-- Peer-to-peer task board -> multi-agent/REFERENCE.md (teams)

"I need scheduling or automation"

Scheduling?
+-- Recurring cron jobs -> scheduling/REFERENCE.md
+-- One-off scheduled tasks -> scheduling/REFERENCE.md
+-- Event-driven triggers -> scheduling/REFERENCE.md
+-- CLI schedule management -> scheduling/REFERENCE.md

"I need to go to production"

Production?
+-- Error handling and status checks -> production/REFERENCE.md
+-- Cost control and token limits -> production/REFERENCE.md
+-- Observability (OpenTelemetry) -> production/REFERENCE.md
+-- Security and sandboxing -> production/REFERENCE.md
+-- Deployment patterns -> production/REFERENCE.md

Troubleshooting Index

• Agent loop not stopping -> tools/REFERENCE.md (completion tools)
• Tool errors crashing the agent -> agent/gotchas.md or clinecore/gotchas.md
• Provider auth failures -> providers/REFERENCE.md
• Session not persisting -> clinecore/gotchas.md
• Token usage too high -> production/REFERENCE.md (cost control)
• Hub connection issues -> clinecore/gotchas.md
• Plugin not loading -> plugins/REFERENCE.md
• Events not firing -> events/REFERENCE.md

Product Index

API Surfaces

Cross-Cutting Concepts

Package Map

Resources

Repository: https://github.com/cline/cline SDK Source: https://github.com/cline/cline/tree/main/sdk Documentation: https://docs.cline.bot/sdk/overview Discord: https://discord.gg/cline