create-task

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Create a new Harbor task for evaluating agents. Use when the user wants to scaffold, build, or design a new task, benchmark problem, or eval. Guides through instruction writing, environment setup, verifier design (pytest vs Reward Kit vs custom), and solution scripting.

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NPX Install

npx skill4agent add harbor-framework/harbor create-task

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Translated version includes tags in frontmatter
Guide the user through creating a new Harbor task end-to-end. Don't just dump commands — walk them through each decision, especially around the verifier (which is usually the hardest part).

Step 1: Scaffold the task

bash
harbor task init "<org>/<task-name>"
Useful flags:
  • --description "..."
  • --author "Jane Doe <jane@example.com>"
    (repeat for multiple authors)
  • --no-pytest
    — skip the pytest test template (use if planning Reward Kit or custom verifier)
  • --no-solution
    — skip solution/ directory
  • --metadata-template path.toml
    — pre-populate task.toml
Produces:
<task-name>/
├── instruction.md         # Task prompt for the agent
├── task.toml              # Config and metadata
├── environment/Dockerfile # Container definition
├── solution/solve.sh      # Reference solution (optional)
└── tests/test.sh          # Verifier script
If the user wants a multi-step task (ordered steps with per-step instructions, tests, and early stopping against a shared container), scaffold the single-step layout first, then convert to the
steps/
layout described in the Multi-step tasks section below.

Step 2: Write instruction.md

This is the prompt the agent receives. Help the user write it clearly:
  • State the goal concretely — what file to create, what behavior to produce
  • Specify expected outputs — paths, formats, content
  • Include constraints — language, tools, approach
  • Don't leak the tests — describe what "done" looks like, not how you'll check it
Example (from the ssh-key-pair tutorial):
markdown
# SSH Key Pair Generation

Generate an SSH key pair in the files `~/.ssh/id_rsa` and `~/.ssh/id_rsa.pub`.

Don't make them password protected.

Step 3: Build the environment

Edit
environment/Dockerfile
to install dependencies the task needs. The agent works inside this container.
dockerfile
FROM ubuntu:24.04
WORKDIR /app

# Install what the task requires — NOT the solution
RUN apt-get update && apt-get install -y openssh-client && rm -rf /var/lib/apt/lists/*
For multi-container setups, use
environment/docker-compose.yaml
instead (note: most cloud sandbox providers only support Dockerfile).
Test the environment interactively before writing the solution or tests:
bash
harbor task start-env -p "<task-path>" -e docker -a -i
This is usually where task authors realize something is missing from the Dockerfile.

Step 4: Decide how to verify

This is the most important decision. Ask the user: "How do you want to grade this task?" Then help them pick:

Option A: Reward Kit (recommended for most cases)

Use when the verifier has multiple criteria, needs partial credit, uses an LLM/agent judge, or would benefit from composable reusable checks. See the
rewardkit
skill.
Good fit signals:
  • Multiple things to check (file exists + content correct + command works)
  • Subjective quality dimensions (readability, correctness of prose)
  • Want partial credit rather than pass/fail
  • Want to compose built-ins like
    file_contains
    ,
    command_succeeds
    ,
    json_key_equals
tests/test.sh
:
bash
#!/bin/bash
uvx --from 'harbor-rewardkit==0.1.*' rewardkit /tests
Note: the package is named
harbor-rewardkit
but the executable is
rewardkit
, hence
--from 'harbor-rewardkit==0.1.*' rewardkit
. Running
uvx harbor-rewardkit
directly will fail.
Then add
tests/checks.py
and/or
tests/judge.toml
. Invoke the
rewardkit
skill to design the criteria.

Option B: pytest (good for deterministic unit-style checks)

Use when the verification is straightforward assertion-style Python. Default template if
--no-pytest
wasn't passed.
tests/test.sh
:
bash
#!/bin/bash
apt-get update && apt-get install -y curl
curl -LsSf https://astral.sh/uv/0.9.7/install.sh | sh
source $HOME/.local/bin/env

uvx --with pytest==8.4.1 pytest /tests/test_outputs.py

if [ $? -eq 0 ]; then
  echo 1 > /logs/verifier/reward.txt
else
  echo 0 > /logs/verifier/reward.txt
fi
Example
tests/test_outputs.py
:
python
from pathlib import Path

def test_file_exists():
    assert (Path.home() / ".ssh" / "id_rsa").exists()

Option C: Custom shell

For simple single-command checks (e.g. a binary pass/fail from one command):
bash
#!/bin/bash
if diff -q /app/output.txt /tests/expected.txt; then
  echo 1 > /logs/verifier/reward.txt
else
  echo 0 > /logs/verifier/reward.txt
fi

Reward file format (all options)

  • /logs/verifier/reward.txt
    — single number (usually
    0
    or
    1
    )
  • /logs/verifier/reward.json
    {"accuracy": 0.95, "runtime_sec": 1.2}
    for multiple metrics
Always use absolute paths in
test.sh
.

Step 5: Write the solution

Write
solution/solve.sh
— a script that actually solves the task. The Oracle agent runs this to sanity-check that the task is solvable and the tests pass on a correct solution.
bash
#!/bin/bash
ssh-keygen -t rsa -f ~/.ssh/id_rsa -N ""
Make it executable:
chmod +x solution/solve.sh
.

Step 6: Configure task.toml

Walk through the important fields:
toml
[task]
name = "<org>/<task-name>"
description = "One-line description"
keywords = ["jax", "mnist", "rewardkit"]  # always populate — used for search/filtering

[metadata]
difficulty = "easy" | "medium" | "hard"
category = "programming" | "machine-learning" | "gpu" | ...
tags = ["..."]

[environment]
cpus = 1               # CPU cores
memory_mb = 2048       # RAM in MB
storage_mb = 10240     # Disk in MB
allow_internet = true  # Network access

[agent]
timeout_sec = 120.0    # How long the agent has

[verifier]
timeout_sec = 600.0    # How long tests have
Always populate
keywords
.
Pick 3–8 lowercase tokens covering the domain (language/framework/benchmark family), the verifier style (
rewardkit
,
judge-grading
,
pytest
), and any notable hardware (
gpu
). They're surfaced in
harbor datasets list
and registry search.
For Reward Kit judges needing API keys:
toml
[verifier.env]
ANTHROPIC_API_KEY = "${ANTHROPIC_API_KEY}"

Step 7: Verify with the Oracle agent

bash
harbor run -p "<task-path>" -a oracle
Oracle runs
solution/solve.sh
and then the verifier. Reward should be
1.0
. If it's not, debug in this order:
  1. Does
    solve.sh
    actually solve it? (
    start-env -a -i
    and run it manually)
  2. Does the verifier correctly detect success? (check
    /logs/verifier/
    output)
  3. Are paths correct? (absolute vs relative)
  4. Are dependencies installed in the Dockerfile?

Step 8: Test with a real agent (optional)

bash
harbor run -p "<task-path>" -a terminus-2 -m anthropic/claude-sonnet-4-6
If the task is too easy (every model 1.0) or impossible (every model 0.0), consider adjusting difficulty.

Step 9: Update README.md (always the final step)

harbor task init
leaves
README.md
as a stub. Before wrapping up, populate it so future humans (and agents) can understand the task without reading every file. Include:
  • What the agent does — one paragraph, link to
    instruction.md
    .
  • Environment — base image, key installed packages, cached data, hardware (GPU/CPU/RAM), agent timeout.
  • Verifier — for Reward Kit tasks, a table of reward dimensions with type (programmatic / LLM judge / agent judge) and what each measures; how they're aggregated.
  • Layout — a tree of the task directory with one-line annotations.
  • Running — the concrete
    harbor run
    commands (Oracle + real agent), with the right provider flag if the task needs a GPU.
Treat this as docs, not marketing — the reader wants to know what they'd need to change to modify the task.

Multi-step tasks

Use when the work splits into ordered phases that should be scored separately, when you want early stopping between phases, or when you're testing an agent's ability to build on its own prior work. Steps share one container; files persist across steps.

Directory layout

Replace the task-root
instruction.md
,
tests/
, and
solution/
with a
steps/
directory containing one sub-directory per step:
<task-name>/
├── task.toml
├── environment/Dockerfile       # Built once, shared across all steps
├── steps/
│   ├── scaffold/
│   │   ├── instruction.md       # Prompt for this step
│   │   ├── workdir/             # Uploaded to WORKDIR before the agent runs
│   │   │   └── setup.sh         # Optional pre-agent hook (reserved filename)
│   │   ├── tests/test.sh        # Per-step verifier
│   │   └── solution/solve.sh    # Per-step Oracle solution (optional)
│   ├── implement/
│   │   └── ...
│   └── document/
│       └── ...
└── tests/                       # Optional shared helpers + fallback test.sh
Task-level
tests/
is uploaded to
/tests
for each step's verification, then the step's own
tests/
is layered on top (same-name files win). Use this for shared helpers.
steps/{name}/workdir/setup.sh
is a reserved filename: if present, it runs after the
workdir/
upload and before the agent, as the step's agent user, with cwd = WORKDIR. Non-zero exit aborts the step and the trial. Have it
rm -- "$0"
on its last line if the agent shouldn't see it.

task.toml

toml
schema_version = "1.1"

[task]
name = "<org>/<task-name>"

# How per-step rewards roll up into the trial-level verifier_result.
# "mean" (default): per-key mean across steps that produced a result.
# "final": the last step's verifier_result verbatim.
multi_step_reward_strategy = "mean"

[[steps]]
name = "scaffold"              # Must match the directory under steps/
min_reward = 1.0               # Abort trial if this step's reward < 1.0
[steps.agent]
timeout_sec = 60.0             # Overrides task-level [agent].timeout_sec
[steps.verifier]
timeout_sec = 30.0

[[steps]]
name = "implement"
# Dict form gates on specific keys from a multi-dim reward:
min_reward = { correctness = 0.8, style = 0.5 }
[steps.agent]
timeout_sec = 120.0
[steps.verifier]
timeout_sec = 30.0

[[steps]]
name = "document"
[steps.agent]
timeout_sec = 60.0
[steps.verifier]
timeout_sec = 30.0
Per-step overrides available:
agent.timeout_sec
,
agent.user
,
verifier.timeout_sec
,
verifier.env
,
verifier.user
,
healthcheck.*
,
artifacts
. Unset fields fall back to the task-level values.

Choosing a reward strategy

  • "mean"
    — aggregate signal across all steps; good for continuous progress rewards.
  • "final"
    — last step's verifier_result is the trial reward. Right when the final step is an end-to-end check whose dict already represents the full task. Caveat: if
    min_reward
    triggers an early abort,
    "final"
    uses the aborted step's result, not the intended final step.

Artifacts

Step-level
artifacts
are collected into
steps/{name}/artifacts/
after that step's verification. Task-level and trial-level artifacts are collected at every step in addition to the step-level ones.

Oracle verification

harbor run -p "<task-path>" -a oracle
runs each step's
solution/solve.sh
, then each step's verifier, in order. Trial reward should be
1.0
across the aggregation strategy.

Full reference + worked example

  • Docs:
    docs/content/docs/tasks/multi-step.mdx
  • Example task:
    examples/tasks/hello-multi-step-advanced/

Special features (mention if relevant)

  • MCP servers: Add
    [[environment.mcp_servers]]
    in task.toml for agent tooling
  • Healthcheck: Add
    [environment.healthcheck]
    for services that need to be ready
  • GPU: Set
    environment.gpus
    and optionally
    environment.gpu_types
  • Pre-built image: Set
    environment.docker_image
    instead of building from Dockerfile
  • Non-root user: Set
    agent.user
    /
    verifier.user
    for isolation

Common pitfalls

  • Forgetting to write the reward file → task "passes" silently with reward 0
  • Using relative paths in
    test.sh
    → breaks when Harbor runs it from a different cwd
  • Installing the solution into the Dockerfile → agent already gets the answer
  • Test script leaks into
    instruction.md
    → agent sees the rubric and gaming becomes trivial
  • Forgetting
    chmod +x solution/solve.sh
    → Oracle agent fails
  • Leaving
    keywords = []
    in task.toml → task is invisible to registry search
  • Leaving
    README.md
    as a stub → teammates have no way to understand the task at a glance