[BUG] Skill workflow stops after sub-skill invocation despite MANDATORY CONTINUATION directives

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Description

When a Claude Code skill invokes a sub-skill using the Skill tool, the workflow stops after the sub-skill completes, even when the parent skill explicitly instructs Claude to continue immediately. The model appears to treat the sub-skill completion as a natural stopping point, ignoring continuation directives in the parent skill.

Environment

Claude Code CLI (VS Code extension)
Model: claude-opus-4-5-20251101
OS: Windows 11
Scenario
A parent skill orchestrates a multi-phase workflow that includes:

Check if an artifact exists locally
If not, invoke a sub-skill to download/generate the artifact
Continue with the next phase of the workflow
The sub-skills handle artifact retrieval (downloading, caching, converting files). The parent skill coordinates multiple sub-skills and analysis steps.

Steps to Reproduce

Create a parent skill with multiple phases that invokes sub-skills via the Skill tool
Add explicit continuation instructions after sub-skill invocations:

### Phase C: Ensure Artifact is Available Check if artifact exists locally... If artifact doesn't exist: Invoke the sub-skill: Use the Skill tool with skill: "download-artifact", args: "<identifier>" MANDATORY CONTINUATION: When the Skill tool returns, your VERY NEXT action must be Phase D. Do NOT: - Report "download complete" or "already cached" to the user - Ask if the user wants to continue - Summarize what was downloaded - Wait for any user input Instead, IMMEDIATELY proceed to Phase D. Invoke the parent skill Observe behavior when the sub-skill completes

What Should Happen?

Expected Behavior

After the sub-skill completes, Claude should immediately continue executing the next phase of the parent skill's workflow without stopping.

Actual Behavior

Claude stops after the sub-skill completes and outputs something like:

"Download complete. Files stored in .cache/component/version/"
"Artifact is already cached."
Then waits for user input instead of continuing the workflow.

Error Messages/Logs

Steps to Reproduce

Parent Skill (SKILL.md):

## Instructions ### Phase A: Validate Input Parse user input and set variables. ### Phase B: Ensure Artifact Available Invoke sub-skill: Use the Skill tool with skill: "get-artifact", args: "<id>" MANDATORY CONTINUATION: When Skill tool returns, IMMEDIATELY proceed to Phase C. ### Phase C: Process Artifact [Continue processing...]

Sub-Skill (get-artifact/SKILL.md):

## Instructions 1. Check if artifact is cached 2. If not cached, download it 3. Report result to user Result: Workflow stops after Phase B sub-skill completes, never reaches Phase C.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.23

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_