What it means
The Moral of Fable
Dan Shipper on what changes when agents can stay on a hard problem for hours.
Read The Moral of Fable →Fable 5 is the best coding model in the world, especially for your most ambitious projects. Before jumping to Fable, find the use cases in your context. Then use 13 copy-ready prompts based on how Anthropic's Mike Krieger and the Every team use it, plus the full interview transcripts behind them. Use this to plan, build, research, verify, and hand off complex work that runs for hours.
Exclusive interview
Mike Krieger, Instagram cofounder and head of Anthropic Labs, has used Fable 5 for months. In this conversation with Dan Shipper, he explains how he delegates work overnight, plans before building, and verifies what the model ships.
Mike has used Fable for months inside Anthropic. Every turned four workflows from this conversation into templates you can use.
Start with the job
Before you spend the tokens
Use Fable when the job:
Use Codex or another model when:
Set up the workspace
Fable is most useful inside Claude Code, where it can inspect your sources, use tools, orchestrate subagents, and verify what it built.
Open the project or working folder, connect the sources and MCPs the job needs, select Fable at high effort, and let it use dynamic workflows, loops, subagents, skills, and verification.
Add the plugin we use daily at Every to guide a full brainstorm, plan, build, review, test, and pull-request pipeline. It also gives Fable a structured way to compound lessons after the run.
Pre-Fable discovery
Use this when: You want to find the use cases in your context that justify a Fable run before spending the time and tokens.
You are helping me decide which parts of my work are worth escalating to Claude Fable 5. Do not execute any of the work yet. Your job is to inspect my context, find strong candidates, and turn the best ones into ready-to-run Fable briefs. My role and current goals: [Describe your role, priorities, team, business goals, creative goals, or personal operating constraints.] Use this context: [List the sources you can inspect: repositories, project folders, docs, Notion, Slack, Linear/Jira, email, calendar, analytics, customer research, previous agent sessions, task lists, or anything else relevant.] Constraints: [List deadlines, privacy boundaries, accounts or tools you may not use, budget, sensitive areas, approval rules, and work that must remain human.] First, inspect the available context. Do not brainstorm generic examples. Build an inventory of: 1. Active projects. 2. Repeated workflows. 3. Stalled decisions. 4. Messy backlogs. 5. Work that spans several tools or sources. 6. Work where better planning, judgment, verification, or follow-through would materially improve the result. Then identify the best candidates for Fable. Score each candidate from 1 to 5 on: 1. Multi-source context. 2. Delegation fit. 3. Judgment required. 4. Clear finish line. 5. Leverage. 6. Fable fit. Recommend Fable only when the task is large enough to justify a slower, more expensive run. Down-rank work that is short, obvious, highly interactive, hard to verify, or better handled by a faster Claude model or a human. Return: 1. The top 10 Fable-worthy use cases, ranked. 2. The evidence you found for each one. 3. Why each one is or is not worth Fable specifically. 4. The expected deliverable. 5. The verification method. 6. The likely context, tools, and permissions needed. 7. Risks, blockers, or human decisions required. 8. A ready-to-run Fable Brief for the top three candidates. For each ready-to-run Fable Brief, include: - The problem to solve. - The final outcome. - Sources to inspect. - Constraints. - Suggested workflow. - Human checkpoints. - Evidence required before completion. Stop after the ranked list and the three briefs. Do not start any Fable task until I choose one.
Why we use it: It lets a faster Claude model inspect real context, down-rank work that belongs with a human or lighter Claude run, and package the best candidates as ready-to-run Fable Briefs.
Start here
Use this when: You have a large task in mind but have not yet turned it into an agent-ready assignment.
I want you to solve this problem: [Describe the underlying problem. Include the first task or deliverable only if it helps explain the problem.] The result I want is: [Describe the final outcome, what good looks like, and how the result will be used.] Use these sources: [List the repositories, documents, research, data, meeting notes, Slack threads, examples, tools, accounts, and other context available to the agent.] Important constraints: [List the audience, deadline, budget, scope, approvals, security boundaries, brand rules, and decisions that must remain human.] Use dynamic workflows, subagents, loops, verification, and installed skills when they fit the job. For software work, use Compound Engineering's LFG pipeline. After a meaningful run, use Compound Engineering to save the lessons worth keeping. Before executing: 1. Inspect the source material. 2. Restate the problem you believe you are solving. 3. Identify missing context, conflicting instructions, and assumptions that could change the result. 4. Decide whether the task requires a loop, a dynamic workflow, new infrastructure, or a simpler direct approach. 5. Show me the proposed approach and the evidence you will use to verify the result. After approval, execute the work. Delegate independent work to subagents and keep going while they run. Pause only for a destructive or irreversible action, a real change in scope, or information only I can provide. Do not stop at analysis or recommendations if you have the tools and permission to ship the result. Before reporting progress or completion, audit every claim against a tool result from this session. If something is not verified, say so plainly. When finished, return: 1. The outcome, in one sentence 2. What you completed and the most important decisions you made 3. Evidence that the result works 4. Anything you could not verify 5. What should be saved or improved so the next run is better
Why we use it: It tells Fable what problem to solve, what evidence to use, where human judgment still matters, and what proof to bring back.
Your complete library
The complete library, adapted from the workflows we tested inside Every, Mike Krieger's interview, and questions from our two-hour Fable camp.
Download full prompt pack (.md)Inspired by Mike Krieger
From his interview with Every
Use this when: The task will take hours and can keep moving without your input.
I'm handing you this task to run unsupervised overnight: [describe the task] Done means: [definition of done] Use this context: [repository, documents, access, constraints] Work through the task to completion. If you hit a blocker, do not stop. Use mocks, stubs, or documented assumptions where appropriate. Record each workaround and continue with everything that does not require my decision. By morning, leave me: 1. What you completed 2. What you worked around and why 3. What still needs my decision 4. The evidence that the work functions as intended
Why we use it: Fable knows what done means, how far it can go alone, and what to do when the first path fails.
Nityesh Agarwal
Senior applied AI engineer
Use this when: An agent keeps failing, running slowly, or producing expensive, inconsistent work.
Here is a session log from an agent attempting this workflow: [describe workflow] It struggled with: [time, cost, errors, poor outputs, or repeated failures] Analyze where the current tool, skill, or workflow breaks down. Identify the root cause instead of patching the latest symptom. Inspect the session logs, tools, skills, and source files. Find the structural bottleneck, then build the smallest reusable improvement: a skill, command-line tool, hook, workflow, context file, or underlying system change. Test the upgraded workflow against a comparable task. Use a fresh verifier to compare the old and new results on quality, time, cost, and failure rate. Return: 1. The root cause 2. The change you made 3. The before-and-after result 4. The infrastructure that faster or cheaper models can reuse 5. Any failure you could not resolve
Why we use it: It sends Fable after the source of the failure, then asks it to leave behind a fix that cheaper models can reuse.
Austin Tedesco
Head of growth
Use this when: A strategy needs to reconcile customer research, analytics, internal plans, and conflicting assumptions.
Use the attached source pack to analyze [business area, launch, audience, or funnel]. Sources include: [survey data, customer research, analytics dashboards, website context, planning documents, meeting notes, Slack discussions, and internal goals] Our goal is [specific business goal] for [target customer or profile]. Test our assumptions against the evidence. Do not treat internal consensus as fact. First produce: 1. The 10 findings most likely to change how we operate 2. A ranked list of 10 things we should ship, test, or stop doing 3. The evidence behind each recommendation 4. Source conflicts, stale rules, unclear metric definitions, and assumptions that need verification Flag conclusions that depend heavily on one source or internal rule. Then stop for me to choose what to act on. After I choose, execute the approved work. For software changes, use the Compound Engineering LFG pipeline to brainstorm, plan, build, review, test, and prepare a pull request. Build missing infrastructure when it blocks the result. Verify the work in the real environment and do not merge or deploy without my explicit approval.
Why we use it: Fable gets the same messy evidence we do, plus permission to challenge the plan and ship the highest-priority fix.
Willie Williams
Head of platform
Use this when: You can provide the same brief, context, and edge cases you would give a senior engineer.
Build a first working version of [product, website, or tool]. Product specification: [paste specification] Users: [who it serves] Domain context: [terms, workflows, examples, and constraints] Tricky cases: [edge cases] Required behavior: [requirements] Acceptable rough edges: [scope boundaries] Use Compound Engineering's LFG pipeline to brainstorm, plan, build, review, and test the first version. Keep the implementation to the stated scope. Test it in the environment where it will be used and prepare a pull request. When you finish, give me: 1. Instructions for trying it 2. The main decisions you made 3. What you left out 4. Test results and other evidence 5. The areas I should review most carefully
Why we use it: The brief gives Fable enough context to build, while making the rough edges and review points explicit.
Inspired by Mike Krieger
From his interview with Every
Use this when: A product or feature needs technical planning and team alignment before implementation.
Before writing code, help me plan [project or feature]. Current context: [what it does, who it serves, and where it runs today] Where it is going: [expected scale, timeline, and release stage] Challenge any infrastructure or abstraction that does not fit this stage. Avoid planning for scale we do not have and avoid shortcuts that will make an imminent release fragile. Work through the tradeoffs with me until we agree on the architecture. Then create one artifact I can share with the team: an HTML page or markdown document with diagrams, the chosen architecture, the alternatives we rejected, and why.
Why we use it: You get the tradeoffs and rejected options in writing before Fable starts making expensive implementation choices.
Inspired by Mike Krieger
From his interview with Every
Use this when: An agent is changing an interface or workflow that needs more than a passing test.
For every change you make to [application or feature], attach evidence that it works. Exercise the real flows using [staging or test account] and representative data. Capture screenshots of every screen you changed, including error states and edge cases. Record a short video of the main flow. Review your own captures. Scrub through the video and flag broken animations, layout shifts, missing states, and anything a user could encounter that the tests did not cover. Return the test results, screenshot gallery, video, issues you found, and any remaining uncertainty.
Why we use it: Fable has to look at the product a user will see and bring back screenshots, video, and remaining uncertainty.
Inspired by Mike Krieger
From his interview with Every
Use this when: A migration is too large for one pass and needs its own repeatable execution system.
I need [codebase or module] ported from [language A] to [language B] because [reason]. Before starting the port, design the workflow and show it to me in code. The workflow should: 1. Map the existing system and write a specification of its behavior. 2. Translate it module by module. 3. Test each module as it is translated. 4. Run an adversarial review at the end for omissions and behavior changes. 5. Document anything deliberately excluded from the port and why. After I approve the workflow, run it from start to finish. When the port is complete, show me where it improves on the original, where behavior may differ, and which areas deserve the closest human review.
Why we use it: Fable designs the migration process first, tests each stage, and shows you where behavior may have changed.
Kieran Klaassen
Cora general manager
Use this when: Feedback is scattered across Slack, support, recordings, customer calls, and production data.
Collect feedback about [product, feature, or workflow] from: [Slack channel, support tickets, screen recordings, screenshots, production logs, customer calls, and meeting notes] Group the feedback into themes. Separate: 1. Changes that are clearly actionable 2. Decisions that require my judgment 3. Requests that conflict with our strategy, user profile, or product direction 4. The evidence supporting each theme Keep a record of what you have already processed so feedback is not duplicated. Create one coherent plan for the actionable changes. After I approve the plan, use Compound Engineering's LFG pipeline to implement them as one batch. Run product polish and verification before handing the result back. Return what changed, what you skipped, what still needs review, the pull request, and the evidence that the changes work. Leave merging and closing the feedback loop to me.
Why we use it: Fable can trace a complaint back to the source, group related changes, and hand the judgment calls back to a person.
Nityesh Agarwal
Senior applied AI engineer
Use this when: The work has many stages or subagents and a fixed linear plan is likely to break.
I need you to complete this complex task: [Describe the task, final outcome, and why it matters.] Available context and tools: [List the sources, repositories, tools, accounts, environments, and constraints.] Use Claude's dynamic workflows to orchestrate the work. The workflow should: 1. Break the task into phases with a clear purpose and completion test. 2. Decide which phases can run in parallel and which depend on earlier work. 3. Assign research, building, testing, and adversarial review to separate subagents where useful. 4. Persist important intermediate findings so later phases can use them. 5. Re-plan when new evidence invalidates the current path. 6. Continue until the definition of done is satisfied, even if the workflow changes along the way. Show me the workflow, likely failure points, and the small number of checkpoints where human judgment is genuinely required. After approval, execute it from start to finish. Keep independent subagents running in parallel and re-plan when evidence changes. Return the result, the evidence, the workflow you used, and the places where it changed.
Why we use it: Fable can change the plan as it learns, while preserving the checkpoints where a person needs to decide.
Dan Shipper
Cofounder and CEO
Use this when: You expect the same class of work or feedback to happen again.
I want to turn this recurring job into a loop: [Describe the recurring input, desired output, current process, and frequency.] Examples of previous inputs and outputs: [Attach representative examples, including failures and human corrections.] Use Claude's loop capability to design and test a loop that: 1. Collects or detects new input. 2. Tracks what it has already processed and avoids duplicate work. 3. Decides whether the input is actionable. 4. Plans and delegates the work. 5. Produces or ships the output. 6. Verifies the result against explicit standards. 7. Routes decisions that require human judgment. 8. Retries recoverable failures and records unrecoverable ones. 9. Captures corrections and updates the system so the next run improves. Identify the trigger, schedule, context, tools, permissions, state, memory, and model-routing rules the loop needs. Use Fable for the hard judgment and orchestration; use faster models for routine stages. Build the smallest working version. Return: 1. A diagram or written map of the loop 2. The working implementation or implementation plan 3. The human checkpoints 4. The verification method 5. How learning will be saved between runs
Why we use it: The prompt turns a recurring job into something that can run again, route exceptions, and learn from corrections.
Katie Parrott
Staff writer
Use this when: Important context is scattered, stale, duplicated, or difficult for an agent to find.
Audit the context available for this body of work: [Describe the project, role, or recurring workflow.] Current sources: [List folders, documents, databases, repositories, meeting notes, style guides, examples, and memory files.] Design an agent-ready context system. The system should: 1. Give Claude Code one concise CLAUDE.md starting file. 2. Explain what each source contains and when to use it. 3. Separate stable rules from temporary project context. 4. Identify conflicts, duplication, stale guidance, and missing information. 5. Include examples of excellent output and known failure modes. 6. Keep large source files available without forcing every run to load everything. 7. Move repeatable procedures into skills instead of bloating CLAUDE.md. 8. Define how new decisions and corrections should be saved. Create the directory, index files, or markdown templates required to make the system usable. Implement the structure when you have the tools and permission. Return the new context map, what you changed, unresolved conflicts, and instructions for keeping it current.
Why we use it: Fable gets one clear place to start, knows which sources outrank others, and can flag stale or conflicting guidance.
Katie Parrott
Staff writer
Use this when: You have a rich archive of ideas and reporting, but the argument or story has not yet taken shape.
Help me develop this writing idea: [Describe the idea, tension, question, or story you are considering.] Use this context: [Attach interview transcripts, reporting, notes, previous drafts, relevant code or product history, style guidance, and examples of your work.] The piece should ultimately accomplish: [Describe the audience, intended effect, central tension, and what a strong piece would make the reader understand or feel.] Explore the material before drafting. 1. Inspect the context and identify the most interesting tensions, surprises, scenes, and unresolved questions. 2. Interview me about the choices that require my judgment or personal experience. 3. Propose several possible arguments or narrative shapes. 4. Explain what each version emphasizes and leaves out. 5. Wait for me to choose a direction. After I choose, create an outline that sequences information for a reader who does not share my context. Then draft the piece. Keep the exploratory material separate from the final draft. Flag where the draft relies on an assumption, lacks evidence, or drifts from the outcome I described.
Why we use it: Fable explores the archive before drafting, then stops at the points where the writer needs to choose the argument.
Austin Tedesco
Head of growth
Use this when: A long-running task succeeded, failed, or required meaningful human correction.
Add this instruction to your agent setup: After every completed agent session, ask me: “Do you want to compound this session?” Do not run the compound process automatically. Wait for my approval. Use Compound Engineering's compound skill to review this completed agent session: [Attach the prompt, plan, outputs, tool calls, test evidence, human feedback, and final result.] Determine what should be learned from this run. Separate: 1. Durable lessons that apply to future work 2. Project-specific facts that belong in project context 3. Personal or team preferences 4. Tool or workflow improvements 5. Mistakes that should not become general rules 6. One-off details that should not be saved For every proposed learning: - Cite the evidence from the session. - Explain where it should be stored. - Show the exact change you propose. - Check for conflicts with existing instructions. Store durable solutions in the project's knowledge system with enough title, metadata, vocabulary, and cross-links for a future agent to find them. Update CLAUDE.md only for concise instructions that belong in every session. Put repeatable procedures in skills. Keep each change small and specific. Return: 1. What you saved 2. Where you saved it 3. What you deliberately did not save 4. How the next run should improve
Why we use it: It saves the lesson that should survive the session without turning every one-off detail into a permanent rule.
Member recording
Dan Shipper, Austin Tedesco, Kieran Klaassen, Katie Parrott, and Nityesh Agarwal show the actual work they gave Fable, what came back, and where they still stepped in.
What it means
Dan Shipper on what changes when agents can stay on a hard problem for hours.
Read The Moral of Fable →
Our hands-on review
We tested Fable 5 across coding, product, growth, and research. Read where it earned its cost, where it struggled, and which jobs fit it best.
Read the Fable 5 Vibe Check →We use analytics and advertising tools by default. You can update this anytime.
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