Templating

Agentic workflows support four templating and substitution mechanisms: GitHub Actions expressions in frontmatter or markdown, conditional markdown blocks, compile-time imports, and runtime imports for files or URLs.

GitHub Actions Expressions

Agentic workflows restrict expressions in markdown content so prompts cannot expose secrets or environment variables to the LLM.

Note: These restrictions apply only to markdown content. YAML frontmatter can still use secrets and environment variables for workflow configuration.

Markdown allows event properties (github.event.*), repository context (github.actor, github.owner, github.repository, github.server_url, github.workspace), run metadata (github.run_id, github.run_number, github.job, github.workflow), and pattern expressions such as needs.*, steps.*, and github.event.inputs.*.

Activation Outputs

Use steps.sanitized.outputs.text, .title, or .body in markdown prompts to access sanitized event content. text includes the full sanitized context (title + body for issues and PRs, body for comments), while title and body expose those fields individually.

Other activation outputs such as comment_id, comment_repo, and slash_command are available as needs.activation.outputs.* in downstream jobs, not in the markdown prompt itself.

Prohibited Expressions

All other expressions are disallowed, including secrets.*, env.*, vars.*, and complex functions like toJson() or fromJson().

Expression safety is validated during compilation. Unauthorized expressions produce errors like:

error: unauthorized expressions: [secrets.TOKEN, env.MY_VAR].
allowed: [github.repository, github.actor, github.workflow, ...]