Inject OPENCODE_SESSION_ID into shell command environment #12158

Problem

There’s no consistent way for shell commands executed by OpenCode to know which session they belong to.

Proposed change

Inject OPENCODE_SESSION_ID into the environment of shell commands executed by OpenCode:

• Bash tool execution
• User-run command path in session prompt

Expected behavior

Commands can access the current session id via OPENCODE_SESSION_ID.

Why this is useful

This is especially important for skills. Skills often orchestrate shell tools and external scripts; having a session-scoped env var makes it possible to tag logs/artifacts and keep skill-side output correlated with the active OpenCode session.

Notes

This does not change PTY terminals or other spawned processes unless explicitly extended later.