OPENCODE/AGENT env vars not propagated to bash tool child processes (Bun compiled binary)

[matthewp]

Problem

OpenCode sets process.env.OPENCODE = "1" and process.env.AGENT = "1" in a yargs middleware (source), but these vars are not visible in child processes spawned by the bash tool.

Root cause

OpenCode is compiled with bun build --compile. Bun's child_process.spawn does not inherit runtime process.env mutations when no explicit env option is passed — it snapshots the environment at startup.

// In Bun (not Node.js):
process.env.FOO = "1";
execSync("echo $FOO");                        // prints empty
execSync("echo $FOO", { env: process.env });   // prints "1"

The V2 bash tool (packages/core/src/tool/bash.ts:159) creates ChildProcess.make() without an env option, so the runtime-set vars never reach child shells.

Impact

Libraries like am-i-vibing and @vercel/detect-agent cannot detect OpenCode. This breaks automatic agent-mode behavior in tools like Astro (which auto-starts astro dev as a background process when an agent is detected).

Repro

From within an OpenCode session:

echo "OPENCODE=$OPENCODE AGENT=$AGENT OPENCODE_PID=$OPENCODE_PID"
# Output: OPENCODE= AGENT= OPENCODE_PID=

Suggested fix

Pass env: process.env explicitly in the bash tool's ChildProcess.make() call, or set the env vars before the Bun compile snapshot.

Version

opencode 1.17.3 (Homebrew, macOS arm64)

[matthewp]

Sorry, my agent went rogue.