Hooks
~2 min read
Concept & How It Works
- Key points are in the visual diagram above.
Why Does It Exist?
Policy that lives only in the prompt is ignored under pressure.
Real-World Analogy
Git hooks, but for the agent.
Visual Workflows
What is Hooks?
Example
Scenario
Scenario (Claude Agent SDK): A user triggers a workflow that depends on Hooks. Hooks run before and after tool calls: log, block, rewrite args, or inject extra context. Your implementation handles the request, logs the step for observability, validates the output, and returns a grounded response — e.g. cutting manual work from 20 minutes to under 30 seconds.
Solution
In Claude Agent SDK, apply Hooks to this scenario: Scenario (Claude Agent SDK): A user triggers a workflow that depends on Hooks. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.
Practice Task
Do this before moving to the next module — reading alone is not enough.
Open the Code Walkthrough below and run it locally. Change one parameter related to Hooks (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.
Code Walkthrough
Highlighted lines show where Hooks happens in the code.
1# Hooks — minimal example2from openai import OpenAI3
4client = OpenAI() # create API client5
6# Ask the model to explain this topic7response = client.chat.completions.create( # core API call for Hooks8 model="gpt-4o-mini",9 messages=[10 {"role": "system", "content": "You explain hooks clearly."},11 {"role": "user", "content": f"What is hooks?"},12 ],13 temperature=0,14)15print(response.choices[0].message.content) # show output for debuggingCommands to Remember
Commands to Remember
npm install @anthropic-ai/claude-agent-sdk # Claude Agent SDKpip install claude-agent-sdk # Python Claude Agent SDK
Common Mistakes
- Skipping evaluation for Hooks before production
- No logging or tracing around claude hooks steps
- Ignoring cost and latency implications
Cheat Sheet
Quick recap — the most important points from this module.
Cheat Sheet
quick ref- •Hooks run before and after tool calls: log, block, rewrite args, or inject extra
