Buildkite Agent Runtime

The

buildkite-agent

binary provides subcommands for interacting with Buildkite from within running job steps — creating annotations, uploading artifacts, sharing state between jobs, generating dynamic pipelines, requesting OIDC tokens, and more. This skill covers the command syntax, flags, and patterns for every in-job subcommand.

Quick Start

A step that runs tests, annotates failures, uploads coverage, and stores a result flag for downstream jobs:

yaml

steps:
  - label: ":test_tube: Tests"
    command: |
      if ! make test 2>&1 | tee test-output.txt; then
        buildkite-agent annotate --style "error" --context "test-failures" < test-output.txt
        buildkite-agent meta-data set "tests-passed" "false"
        exit 1
      fi
      buildkite-agent annotate "All tests passed :white_check_mark:" --style "success" --context "test-results"
      buildkite-agent artifact upload "coverage/**/*"
      buildkite-agent meta-data set "tests-passed" "true"

A downstream step reading that state:

yaml

  - label: ":rocket: Deploy"
    command: |
      PASSED=$(buildkite-agent meta-data get "tests-passed")
      if [[ "$PASSED" != "true" ]]; then
        echo "Tests did not pass, skipping deploy"
        exit 0
      fi
      scripts/deploy.sh
    depends_on: "test-step"

Annotations

Surface build results directly on the build page. Annotations support Markdown and HTML.

Creating annotations

bash

# Simple text annotation
buildkite-agent annotate "Deploy completed successfully" --style "success" --context "deploy"

# Pipe from a file
buildkite-agent annotate --style "error" --context "test-failures" < test-output.md

Key flags

Flag	Short	Default	Description
`--style`	`-s`	`default`	Visual style: `default` , `info` , `warning` , `error` , `success`
`--context`	`-c`	random UUID	Unique ID — reusing a context replaces the annotation
`--append`	—	`false`	Append to existing annotation with same context instead of replacing
`--priority`	—	`3`	Display priority (1-10). Higher numbers appear first
`--job`	—	current job	Job ID to annotate (rarely needed)

Replacing vs appending

Same
--context
without
--append
replaces the annotation; with
--append
appends below existing content.
Always use a stable
```
--context
```
value so reruns update the same annotation instead of creating duplicates.

For pipeline-level
notify:
configuration, see the buildkite-pipelines skill.

Artifacts

Upload files as build artifacts, download them in later steps or other builds, and search by glob.

Upload

bash

# Upload a single file
buildkite-agent artifact upload "pkg/release.tar.gz"

# Upload with glob pattern
buildkite-agent artifact upload "dist/**/*"

Download

bash

# Download to current directory
buildkite-agent artifact download "pkg/release.tar.gz" .

# Download from a specific step
buildkite-agent artifact download "dist/*" . --step "build-step"

Search

bash

# List matching artifacts
buildkite-agent artifact search "pkg/*.tar.gz" --build "$BUILDKITE_BUILD_ID"

For complete flag tables, see

references/flag-reference.md

For the declarative
artifact_paths:
YAML key, see the buildkite-pipelines skill. For
bk artifact
CLI commands, see the buildkite-cli skill.

Meta-data

A build-wide key-value store for sharing state between jobs. Set a value in one job, read it in any other job in the same build.

Set

bash

buildkite-agent meta-data set "release-version" "1.4.2"

Get

bash

VERSION=$(buildkite-agent meta-data get "release-version")

Use

--default

to return a fallback value instead of a non-zero exit when the key is missing:

buildkite-agent meta-data get "deploy-env" --default "staging"

Check existence

bash

# Returns exit code 0 if exists, 100 if not
if buildkite-agent meta-data exists "release-version"; then
  echo "Version already set"
fi

Common patterns

Block step field values are stored automatically as meta-data. Retrieve them by field key:

bash

# After a block step with fields: [{key: "release-name", text: "Release Name"}]
RELEASE_NAME=$(buildkite-agent meta-data get "release-name")

Raw webhook payloads are available in webhook-triggered builds, while the webhook data remains cached. Read the special

buildkite:webhook

key when automation needs fields that are not promoted to first-class environment variables, such as the original pull request comment body.

bash

WEBHOOK="$(buildkite-agent meta-data get "buildkite:webhook")"
COMMENT_BODY="$(jq -r '.comment.body' <<< "$WEBHOOK")"

Pipeline Upload

Dynamically add steps to a running build. The core mechanism behind dynamic pipelines — generate YAML at runtime and upload it.

Basic usage

bash

# Upload a specific file
buildkite-agent pipeline upload .buildkite/deploy-steps.yml

# Pipe generated YAML from stdin
./scripts/generate-pipeline.sh | buildkite-agent pipeline upload

Replace mode

By default, uploaded steps are appended after the current step. Use

--replace

to replace the entire remaining pipeline:

bash

# Replace all remaining steps with the uploaded ones
buildkite-agent pipeline upload --replace .buildkite/new-pipeline.yml

Key flags

Flag	Default	Description
`--replace`	`false`	Replace remaining pipeline steps instead of appending
`--no-interpolation`	`false`	Skip environment variable interpolation in the uploaded YAML
`--dry-run`	`false`	Validate and output the pipeline without uploading

For pipeline YAML syntax and step types, see the buildkite-pipelines skill.

OIDC Tokens

Request short-lived OpenID Connect tokens from within a job step for authenticating to external services (cloud providers, package registries) without static credentials.

Basic token request

bash

# Request a token for a specific audience
TOKEN=$(buildkite-agent oidc request-token --audience "https://packages.buildkite.com/my-org/my-registry")

Cloud provider authentication

bash

# AWS — request token with STS audience
TOKEN=$(buildkite-agent oidc request-token --audience "sts.amazonaws.com")

Key flags

Flag	Default	Description
`--audience`	Buildkite endpoint	Target service URL — must match the OIDC provider audience configuration
`--lifetime`	`0` (API default)	Token lifetime in seconds. When 0 or omitted, the API chooses a default lifetime
`--claim`	—	Optional claims to include (e.g., `organization_id,pipeline_id` ). Repeatable
`--aws-session-tag`	—	Claims to map as AWS session tags. Repeatable

For end-to-end OIDC auth flows, cloud provider setup, and token claim details, see the buildkite-secure-delivery skill.

Step Management

Read or modify step attributes at runtime. Useful for conditional logic within steps and build automation.

Get step attributes

bash

# Get a step's label (--step is required)
LABEL=$(buildkite-agent step get "label" --step "$BUILDKITE_STEP_KEY")

# Get another step's state
STATE=$(buildkite-agent step get "state" --step "deploy-step")

# Get the entire step as JSON
buildkite-agent step get --step "test-step" --format json

Update step attributes

bash

# Update a step's label dynamically
buildkite-agent step update "label" ":rocket: Deploying v${VERSION}" --step "$BUILDKITE_STEP_KEY"

# Append to an existing label
buildkite-agent step update "label" " (retried)" --step "build-step" --append

Cancel a step

bash

# Cancel all unfinished jobs for a step
buildkite-agent step cancel --step "optional-step"

# Force-cancel a running step
buildkite-agent step cancel --step "stuck-step" --force

Key flags

Flag	Default	Description
`--step`	—	Step key or UUID to target (required — uses `$BUILDKITE_STEP_ID` env var if set)
`--build`	current build	Build UUID (for cross-build operations)
`--format`	—	Output format for `get` (use `json` for complex attributes)
`--append`	`false`	Append to existing value instead of replacing ( `step update` only)
`--force`	`false`	Force cancel even if the step is running ( `step cancel` only)

Distributed Locks

Coordinate parallel jobs within a build using distributed mutex locks. Prevents race conditions when multiple jobs access shared resources.

Acquire / release pattern

bash

#!/bin/bash
set -euo pipefail

# Acquire lock — blocks until available, returns a token
token=$(buildkite-agent lock acquire "database-migration")
trap 'buildkite-agent lock release "database-migration" "${token}"' EXIT

# Critical section — only one job runs this at a time
bundle exec rails db:migrate

Do / done pattern (one-time setup)

Run a setup task exactly once across all parallel jobs:

bash

#!/bin/bash
echo "+++ Setting up shared test environment"

if [[ $(buildkite-agent lock do "test-env-setup") == "do" ]]; then
  echo "Downloading test assets..."
  curl -o /tmp/test-data.zip https://releases.example.com/data.zip
  unzip /tmp/test-data.zip -d /tmp/shared-test-files/
  buildkite-agent lock done "test-env-setup"
else
  echo "Assets already prepared by another job"
fi

# All jobs continue here
run-tests.sh

Key flags

Subcommand	Flags	Description
`lock acquire <name>`	`--lock-wait-timeout`	Maximum wait duration (e.g. `30s` , `5m` ). Default: wait forever
`lock release <name> <token>`	—	Release with the token from `acquire`
`lock do <name>`	—	Returns `do` if lock acquired, `done` if already completed
`lock done <name>`	—	Mark a `do` lock as completed

Environment

Inspect and modify the job's environment variables. Primarily useful for debugging lifecycle hooks and understanding what environment changes hooks made.

bash

# Dump all environment variables as JSON
buildkite-agent env dump | jq .

# Get a specific variable
buildkite-agent env get "BUILDKITE_BRANCH"

# Set variables for subsequent hooks and the command (KEY=value format)
buildkite-agent env set DEPLOY_TARGET=production "APP_NAME=My App"

Key flags

Subcommand	Description
`env dump`	Dump all environment variables (JSON format by default)
`env get <keys...>`	Get one or more specific variables. Use `--format` for output format ( `plain` , `json` , `json-pretty` )
`env set KEY=value [...]`	Set variables for subsequent phases. Accepts multiple `KEY=value` pairs
`env unset <key>`	Remove a variable from subsequent phases

Debugging hooks

The

env dump

command is particularly useful in lifecycle hooks to see what prior hooks changed:

bash

#!/bin/bash
# .buildkite/hooks/pre-command
echo "--- Environment after environment hook:"
buildkite-agent env dump | jq 'keys'

For agent lifecycle hooks and
buildkite-agent.cfg
configuration, see the agent hooks and agent configuration documentation.

Secrets

Retrieve cluster secrets at runtime from within job steps. Secrets retrieved this way are automatically added to the log redactor.

Basic usage

bash

# Get a secret value
SECRET_VAR=$(buildkite-agent secret get "deploy-key")

# Pass directly to a tool
cli-tool --token "$(buildkite-agent secret get "api-token")"

Key flags

Flag	Default	Description
`--format`	`default`	Output format: `default` (single secret prints value, multiple prints JSON), `json` , or `env` (KEY="value" pairs)
`--skip-redaction`	`false`	Do not add the secret value to the log redactor
`--job`	current job	Job ID context

Multiple secret keys can be requested at once:

buildkite-agent secret get KEY1 KEY2 KEY3

By default,

secret get

automatically registers retrieved values with the log redactor, masking them as

[REDACTED]

in subsequent output.

For setting up cluster secrets, see the Buildkite Secrets documentation. For the declarative
secrets:
pipeline YAML key, see the buildkite-pipelines skill.

Log Redaction

Add values to the build log redactor at runtime so they are masked in all subsequent output. Use this for dynamically-retrieved secrets that were not declared via

secrets:

buildkite-agent secret get

Basic usage

bash

# Fetch a token from an external source
DYNAMIC_TOKEN=$(curl -s https://vault.example.com/token)

# Register it with the redactor before using it
echo "$DYNAMIC_TOKEN" | buildkite-agent redactor add

# Now any log output containing the token value shows [REDACTED]
echo "Using token: $DYNAMIC_TOKEN"
# Output: Using token: [REDACTED]

Multiple values

bash

# Redact multiple values
echo "$SECRET1" | buildkite-agent redactor add
echo "$SECRET2" | buildkite-agent redactor add

When to use redactor vs secret get

Scenario	Use
Secret stored in Buildkite cluster secrets	`buildkite-agent secret get` (auto-redacts)
Secret from external vault (HashiCorp Vault, AWS SSM, etc.)	Fetch externally, then `buildkite-agent redactor add`
Computed sensitive value (temporary token, derived key)	`buildkite-agent redactor add`

Tool Signing

Sign pipeline YAML so that agents can verify step integrity before execution. The

tool sign

command takes a pipeline file (not individual steps) and annotates it with signatures.

Sign a pipeline from a file

bash

# Sign a pipeline YAML file using a local JWKS key
buildkite-agent tool sign pipeline.yml \
  --jwks-file /path/to/private-key.json \
  --repo "git@github.com:org/repo.git"

Sign via the GraphQL API

bash

# Retrieve, sign, and update a pipeline via the Buildkite GraphQL API
buildkite-agent tool sign \
  --graphql-token "$BUILDKITE_GRAPHQL_TOKEN" \
  --organization-slug my-org \
  --pipeline-slug my-pipeline \
  --jwks-file /path/to/private-key.json \
  --update

Generate a signing key pair

bash

# Generate a new JWS key pair (private + public JWKS files)
buildkite-agent tool keygen

Key flags

Command	Flag	Description
`tool sign`	`--jwks-file`	Path to JWKS private key file for signing
`tool sign`	`--jwks-key-id`	Key ID to use from the JWKS file
`tool sign`	`--repo`	Repository URL (required when signing from a file)
`tool sign`	`--signing-aws-kms-key`	AWS KMS key ID for signing (alternative to JWKS)
`tool sign`	`--signing-gcp-kms-key`	GCP KMS key ID for signing (alternative to JWKS)
`tool sign`	`--graphql-token`	Token for retrieving/updating pipeline via GraphQL API
`tool sign`	`--update`	Update the pipeline in Buildkite after signing (requires `--graphql-token` )
`tool keygen`	`--alg`	JWS signing algorithm (default: `EdDSA` )
`tool keygen`	`--key-id`	Key ID for the generated pair (default: random)

Note: There is no
tool verify
command. Signature verification is handled internally by the agent when it receives a job.

For pipeline signing configuration and rollout strategy, see the buildkite-secure-delivery skill.

Common Mistakes

Mistake	What happens	Fix
Missing `--context` on `annotate`	Each call creates a new annotation instead of updating	Always pass `--context` with a stable identifier
Using `--append` without matching `--context`	Append has no effect — creates a new annotation	Ensure `--context` matches the annotation to append to
Forgetting to quote artifact glob patterns	Shell expands globs before `buildkite-agent` sees them	Always quote: `"dist/*/"` not `dist/*/`
Reading `meta-data get` before the writing job completes	Key does not exist, command fails with non-zero exit	Use `depends_on` or `wait` to enforce ordering, or use `--default`
Using `pipeline upload --replace` unintentionally	Removes all remaining steps in the build	Only use `--replace` when intentionally rebuilding the entire pipeline
Not releasing locks on script failure	Lock held indefinitely, blocking other jobs	Use `trap ... EXIT` to release locks on any exit
Passing `--audience` that doesn't match OIDC provider config	Token rejected by the target service	Audience must exactly match the provider's configured audience URL
Using `--skip-redaction` with actual secrets	Secret values appear in plain text in build logs	Only use `--skip-redaction` for non-sensitive configuration values
Calling `env set` expecting it to affect the current shell	Variable is set for subsequent hooks/phases, not the current script	Use `export VAR=value` for current-script variables; `env set` for cross-phase
Passing large values via environment variables	OS-level env size limits cause silent truncation or job failure	Switch to file-based approaches (artifacts, meta-data with files) for payloads larger than a few KB
Uploading pipeline YAML with unescaped `$` in `--no-interpolation` mode off	Variables interpolated unexpectedly, producing malformed YAML	Use `--no-interpolation` when YAML contains literal `$` characters

Additional Resources

Reference Files

references/flag-reference.md
— Complete flag tables for all subcommands including upload, download, search, shasum, annotate, meta-data, pipeline upload, oidc, step, lock, env, secret, redactor, and tool
references/patterns-and-recipes.md
— Advanced multi-subcommand patterns: test failure annotation pipelines, cross-job state machines, OIDC-authenticated Docker push, parallel job coordination with locks, environment debugging

buildkite-agent-runtime

NPX Install

Tags

SKILL.md Content

Buildkite Agent Runtime

Quick Start

Annotations

Creating annotations

Key flags

Replacing vs appending

Artifacts

Upload

Download

Search

Meta-data

Set

Get

Check existence

Common patterns

Pipeline Upload

Basic usage

Replace mode

Key flags

OIDC Tokens

Basic token request

Cloud provider authentication

Key flags

Step Management

Get step attributes

Update step attributes

Cancel a step

Key flags

Distributed Locks

Acquire / release pattern

Do / done pattern (one-time setup)

Key flags

Environment

Key flags

Debugging hooks

Secrets

Basic usage

Key flags

Log Redaction

Basic usage

Multiple values

When to use redactor vs secret get

Tool Signing

Sign a pipeline from a file

Sign via the GraphQL API

Generate a signing key pair

Key flags

Common Mistakes

Additional Resources

Reference Files

Further Reading