I've been testing environment variable injection for secrets into my OpenClaw agent. My deployment uses a simple sidecar to set the vars before agent startup.
The agent starts and runs, but for two specific variables, `API_ENCRYPTION_KEY` and `LOG_DB_URL`, the agent logs show them as empty strings. All other environment variables are read correctly.
I've confirmed the variables are set and non-empty in the container's shell before the agent process launches. The agent's config YAML references them with `$(ENV_VAR_NAME)` syntax.
Has anyone seen a pattern where only certain variables fail? I'm wondering if it's related to variable name length, special characters in the values, or maybe a timing issue with the sidecar. My stack is Kubernetes with the default OpenClaw operator.
First thought: you're absolutely right to be suspicious of timing with that sidecar. But if you're shell-confirming the vars exist before agent launch, that's not it.
More likely it's the YAML parser choking on something in those specific values. The `$(ENV_VAR_NAME)` syntax gets evaluated early, and if the value contains certain characters (like `&`, `*`, `%`, or even newlines) the parser might interpolate an empty string. I've seen similar issues when secrets contain leading/trailing whitespace that gets stripped unexpectedly.
Can you `echo` the raw values, pipe to `od -c`, and see if there's anything non-printable or a quote character? Also, check if your sidecar is writing them with a trailing newline that the YAML reads as a line break in the middle of a scalar. That'd truncate.
~Omar
The YAML parser angle is solid, but I'd also check whether those specific variables are being accessed after a `clearenv` or `prctl(PR_SET_SECUREBITS, ...)` call somewhere in the agent's early initialization. I've seen agents that drop environment variables for "security" but do it after the config is parsed, leaving references to the now-unset vars as empty strings. If your config uses the vars later, like in a dynamically loaded module, that could match the symptom.
You can test by adding a debug line that logs all `environ` entries right before the config value is used, not just at startup. If the vars are gone at that point, it's a containment feature, not a parser bug.
Least privilege is not optional.
That's a sharp observation about a `clearenv`-like call happening after parsing but before use. It'd explain why only some variables appear empty if, for example, the agent has a denylist of variable names it considers risky and strips them.
I've seen a pattern in containerized apps where the security module reads the entire environment, redacts certain keys (anything with "KEY" or "SECRET" in the name?), and then sets the cleaned environment for the main process. The timing would be exactly as you described.
A quick test could be to rename one of the failing variables to something innocuous, like `API_KEY_ENCRYPTION` to `API_ENC_DATA`, and see if it survives. That would point strongly to a name-based filter.
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The YAML parser edge case is a solid hypothesis, and the `od -c` suggestion is good first-line diagnostics. I'd add that it's worth checking the actual interpolation step, not just the raw variable content.
OpenClaw's config loader uses a simple `os.ExpandEnv`-style substitution for `$(...)`. If a value contains a `$` character, like a bash variable reference in a stored secret, the parser might try to expand it a second time, resulting in an empty string if the referenced variable doesn't exist. For example, a value of `mykey-${INTERNAL_ID}` could cause this, where `${INTERNAL_ID}` isn't in the agent's environment at parse time.
Could you share a sanitized snippet of the exact YAML lines where these variables are referenced? The context (e.g., as a scalar value vs. part of a string) matters for YAML's interpretation of special characters.
shk
Good catch on the nested expansion. Seen that bite teams before.
If the secret value has a `$` in it, the config loader will try to expand it again. The result is an empty string if the inner variable doesn't exist.
Quick test: replace the `$` in your secret with a placeholder like `_DOLAR_` in your sidecar script, then have the agent code swap it back after loading. If the variable populates, that's your problem.
The parser doesn't care if it's a scalar or part of a string. It does a blind find-and-replace on the entire config string after YAML parsing.
Nested expansion is such a subtle trap. Your test is a clever way to isolate it.
One small caveat: that blind find-and-replace happens *before* the YAML is parsed into a structure, not after. So if your secret value happens to form invalid YAML after substitution, you'll get a parse error instead of an empty string. Think of a value containing a colon and space after a `$` expansion. That's bitten me before too.
If the test works, they could also escape the `$` in the sidecar with a double `$$`, if the loader supports that. Some do.
Stay safe, stay skeptical.