[owtaylor]

Why:

Closes: N/A

The "Controlling cache access with cache-mode" section says "The runner exposes the effective mode in the ACTIONS_CACHE_MODE environment variable". It's natural to read that as meaning every step can see the variable. But a shell script in a run step sees nothing, even when the job setup log shows Cache mode: read. That makes it look like the feature is broken or not rolled out yet.

In actions/runner, only NodeScriptActionHandler and ContainerActionHandler set ACTIONS_CACHE_MODE in the step environment. JobExtension just logs the mode. The handler for run steps never sets it.

What's being changed (if available, include any code snippets, screenshots, or gifs):

Adds a short note to content/actions/reference/workflows-and-actions/dependency-caching.md, right after the paragraph about ACTIONS_CACHE_MODE:

Note

ACTIONS_CACHE_MODE is only set in the environment of JavaScript and Docker container actions. It is not available to run steps, including run steps in composite actions.

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR. In most cases, the author can be the SME. Open source contributions may require an SME review from GitHub staff.
• The changes in this PR meet the docs fundamentals that are required for all content.
• All CI checks are passing and the changes look good in the review environment.

🤖 Generated with Claude Code

[github-actions]

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Source	Review	Production	What Changed
actions/reference/workflows-and-actions/dependency-caching.md	fpt ghec ghes@ 3.22 3.21 3.20 3.19	fpt ghec ghes@ 3.22 3.21 3.20 3.19

Key: fpt: Free, Pro, Team; ghec: GitHub Enterprise Cloud; ghes: GitHub Enterprise Server

🤖 This comment is automatically generated.

[Copilot]

🔵 Needs a closer look

SME confirmation is needed because the note describes runner behavior absent from this checkout and spanning supported product versions, specifically the JavaScript/container versus run-step distinction.

No open issues 🎉

What changed in this PR

Clarifies the scope of the ACTIONS_CACHE_MODE environment variable in the dependency caching reference, explaining that it is unavailable to shell-based run steps.

Changes:

• Notes that the variable is set only for JavaScript and Docker container actions.
• Clarifies that run steps, including those in composite actions, cannot access it.

File	Description
content/​actions/​reference/​workflows-and-actions/​dependency-caching.md	Documents that ACTIONS_CACHE_MODE is available only to JavaScript and Docker container actions, not to run steps.

_{Review effort: Lite}