Why do I get a 401 Unauthorized error?

Check if your AgentLLM key is valid and correctly passed in the Authorization header. You can regenerate the key under Test → LLM → Keys.

Why is the wrong version of my agent responding?

Check the 'model' string in your request. Make sure you're using the correct version tag like @dev, @prod, or @1.0.

What do I do if my request returns no output?

Confirm that your agent is correctly configured and LLM is toggled on. Then inspect logs under Deployments → Logs.

How do I find the correct baseURL and model string?

Go to Test → LLM → Code. Always copy the baseURL and model directly from there to avoid typos or environment mismatches.

Prompt Engineering with Weaver

Weaver can assemble a workflow from almost any instruction. But if you give it a vague prompt, it will ask follow-up questions and slow you down. If you give it a clear, structured prompt, Weaver has everything it needs to build the agent immediately with no follow-up questions.

The Golden Rule

Write every prompt with Goal → Inputs → Skills → Outputs → Constraints.
That structure gives Weaver complete context and reduces back-and-forth.

1. Why Prompt Engineering Matters

Prompts are the blueprint Weaver uses to create workflows. Clear prompts produce modular, testable agents that run correctly on the first try. Ambiguous prompts create guesswork and messy flows.

If you want ready-made examples, see the Prompt Library. This page teaches you how to write prompts yourself.

2. The Standard Prompt Structure

Every strong Weaver prompt includes these five sections:

Prompt Template

Template

Goal: [Outcome in one clear sentence] Inputs: - [Required user inputs] - [Optional inputs if needed] Skills: 1. [Actionable step 1] 2. [Actionable step 2] 3. [Actionable step 3] Outputs: - [Exact format: JSON schema, Markdown, table, file] Constraints: - [Word limits, item caps, tone, audience] - [Formatting rules or compliance needs]

When you provide all five sections, Weaver has no missing context and it builds the agent right away instead of asking questions.

3. Writing Effective Prompts

Be Specific with Goals

Clear vs Vague Goals

Goals

❌ Vague: "Write about Kyoto." ✅ Clear: "Draft a 600-word blog about Kyoto with three sections: food, culture, and transport."

Break Work into Skills

Skills Example

Skills

Goal: Weekly sales digest Skills: 1. Fetch weekly_sales.csv from S3 2. Summarise data into 5 bullet points 3. Generate bar chart PNG 4. Email digest to [email protected]

Define Outputs and Constraints

Constrain the Output

Constraints

Goal: Create a 5-minute finance podcast script. Skills: 1. Gather 3 finance stories 2. Write intro, 3 sections, and a closing 3. Add one host aside per story Outputs: - Markdown with sections: Intro, Story 1, Story 2, Story 3, Closing Constraints: - Max 700 words - Conversational tone - Exclude stock tips

4. Advanced Prompt Techniques

Add Modifiers

Use constraints to sharpen results.

Modifier Example

Advanced

Goal: Write a one-page product brief. Inputs: - product_name - competitor_names[] Skills: 1. Research competitors 2. Summarise positioning 3. Write product brief Outputs: - Markdown with headings Constraints: - Limit to 350 words - Reading level: Year 9 - Include at least 3 reference links

Few-Shot Anchors

Show Weaver the format you want by including one example.

Few-Shot Example

Style

Goal: Generate a 120-word LinkedIn post. Skills: 1. Capture one clear benefit 2. Add two use cases 3. End with a question Constraints: - Professional but warm tone - 120 words max Example to follow: "We reduced CSV import time by 70%. Teams can now clean data and build reports in one session. What would you import first?"

Multimodal Prompts

Weaver can parse URLs and images directly.

URL Input Example

Multimodal

Goal: Convert a blog post into a help guide. Inputs: - blog_url: string Skills: 1. Read the blog content at {blog_url} 2. Extract step-by-step instructions 3. Rewrite as a numbered help guide Outputs: - Markdown with H2 headings and steps Constraints: - Preserve technical terms from the source

Diagram Input Example

Multimodal

Goal: Build an agent from a workflow diagram. Inputs: - diagram_file: PNG or SVG Skills: 1. Parse the diagram 2. Identify components and connections 3. Recreate the workflow in Canvas Outputs: - Complete wired agent Constraints: - Use labels from the diagram as component names

5. Debugging and Iteration

When results are off, refine the prompt rather than rewriting the entire agent.

Refinement Example

Debugging

The summary was too long. Limit it to 150 words. Format as bullet points only.

Schema Example

Debugging

Return JSON with these keys only: title, slug, summary, keywords[]. No other keys. Missing values = null.

For full troubleshooting, see Debugging with Weaver.

6. Common Mistakes and Fixes

Mistake	Why It Fails	What To Do Instead
Vague goal	Weaver lacks context and asks follow-ups	State a measurable outcome in one sentence
One giant skill	Hard to test or debug	Break into 3–5 numbered steps
Missing constraints	Outputs sprawl or vary	Specify format, tone, and limits
Unlimited output	Token waste and errors	Add caps (e.g., 200 words, 5 bullets)
Ambiguous tone	Wrong style or locale	Define audience, tone, and language (e.g., UK English)

Next Steps

Practice your first structured prompt with the Weaver Quickstart.
Explore curated examples in the Prompt Library.
See how inputs and outputs connect in the Weaver I/O guide.

Was this page helpful?

1. Why Prompt Engineering Matters​

2. The Standard Prompt Structure​

3. Writing Effective Prompts​

Be Specific with Goals​

Break Work into Skills​

Define Outputs and Constraints​

4. Advanced Prompt Techniques​

Add Modifiers​

Few-Shot Anchors​

Multimodal Prompts​

5. Debugging and Iteration​

6. Common Mistakes and Fixes​

Next Steps​