NousResearch/hermes-agent

Pre-compile and unify MCP env-var regex interpolation

Cluster 2711 · mcp. Data as of

Nothing open on GitHub. Fix merged in #26240 on 15 May 2026. Check it covers your case.

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0open issues
0open PRs
4items grouped
Known?
Yes. 4 related items grouped here, 1 issue already closed.
Fix event
A fix was merged to main in PR #26240. Check it covers your case. No release data is tracked.
Tracker
The maintainers' tracker marks this resolved, deciding PR #26240. That is separate from the fix event.
Still open
Nothing open on GitHub.

These items all address the same change: pre-compiling the environment variable interpolation regex in MCP-related code and unifying that interpolation logic across relevant modules. The members appear to be duplicate or iterative versions of the same fix or refactor.

Open issues0

No open issues.

Open PRs0

No open pull requests.

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

  • #26240 fix(mcp): pre-compile env-var regex and unify interpolation

    merged to main

    files: hermes_cli/mcp_config.py, scripts/release.py, tools/mcp_tool.py

    Show the diff
    • hermes_cli/mcp_config.py
      @@ -25,6 +25,7 @@
       )
       from hermes_cli.colors import Colors, color
       from hermes_constants import display_hermes_home
      +from tools.mcp_tool import _ENV_VAR_PATTERN
       
       logger = logging.getLogger(__name__)
       
      @@ -551,7 +552,7 @@ def cmd_mcp_test(args):
               for k, v in headers.items():
                   if isinstance(v, str) and ("key" in k.lower() or "auth" in k.lower()):
                       # Mask the value
      -                resolved = _interpolate_value(v)
      +                resolved = _ENV_VAR_PATTERN.sub(lambda m: os.getenv(m.group(1), ""), v)
                       if len(resolved) > 8:
                           masked = resolved[:4] + "***" + resolved[-4:]
                       else:
      @@ -581,13 +582,6 @@ def cmd_mcp_test(args):
           print()
       
       
      -def _interpolate_value(value: str) -> str:
      -    """Resolve ``${ENV_VAR}`` references in a string."""
      -    def _replace(m):
      -        return os.getenv(m.group(1), "")
      -    return re.sub(r"\$\{(\w+)\}", _replace, value)
      -
      -
       # ─── hermes mcp login ────────────────────────────────────────────────────────
       
       def cmd_mcp_login(args):
    • scripts/release.py
      @@ -111,6 +111,7 @@
           "[email protected]": "oswaldb22",
           "[redacted:email]": "AJV20",
           "[redacted:email]": "masonjames",
      +    "[email protected]": "amethystani",
           "[redacted:email]": "liquidchen",
           "[redacted:email]": "subtract0",
           "[redacted:email]": "ReqX",
    • tools/mcp_tool.py
      @@ -279,6 +279,11 @@ def _check_message_handler_support() -> bool:
           re.IGNORECASE,
       )
       
      +# Pre-compiled pattern for ${VAR_NAME} style env-var interpolation.
      +# Supports any non-} characters in the variable name (hyphens, dots, etc.)
      +# so providers like MY-VAR or my.var work correctly.
      +_ENV_VAR_PATTERN = re.compile(r"\$\{([^}]+)\}")
      +
       
       # ---------------------------------------------------------------------------
       # Security helpers
      @@ -2104,7 +2109,7 @@ def _interpolate_env_vars(value):
           if isinstance(value, str):
               def _replace(m):
                   return os.environ.get(m.group(1), m.group(0))
      -        return re.sub(r"\$\{([^}]+)\}", _replace, value)
      +        return _ENV_VAR_PATTERN.sub(_replace, value)
           if isinstance(value, dict):
               return {k: _interpolate_env_vars(v) for k, v in value.items()}
           if isinstance(value, list):

2 PRs closed without merging

From the close comments: merged via another change 1 · other 1

  • #2719 fix(mcp): pre-compile env-var regex and unify interpolation across mcp_tool and mcp_config · merged via another change → #26240
  • #2728 refactor(mcp): unify env-var interpolation and pre-compile regex · other
Closed issues · 1
  • Closed#2711Pre-compile env-var interpolation regex in mcp_tool.py
How this cluster was grouped
  • Link evidence (structural links throughout): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
  • Pairwise link density 0.50: the share of item pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. 1.00 means every pair is linked.

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At a glance

Subsystem
mcp
Merged PRs
#26240
Closed issues
1
Attempts
2 PRs closed without merging
Fix link checked
15 May 2026

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