daemon: skip malformed/empty DevToolsActivePort instead of crashing

[thomwolf]

Problem

get_ws_url() iterates PROFILES and parses each DevToolsActivePort with .split("\n", 1). An empty or single-line file — e.g. a stale Chrome-CDP profile left behind by a prior run — returns fewer than 2 values, raising ValueError.

That exception wasn't caught, so a single malformed file aborted the entire discovery loop before reaching a valid profile. It surfaced as the cryptic daemon-fatal:

fatal: not enough values to unpack (expected 2, got 1)

This is easy to hit because Chrome-CDP is the first entry in PROFILES (added in a9ba3b9), so a leftover empty port file there shadows the user's real, working Chrome profile.

Fix

Catch ValueError alongside FileNotFoundError/NotADirectoryError so a malformed profile is skipped and discovery falls through to the next one — and ultimately to the actionable DevToolsActivePort not found — enable chrome://inspect... message.

Test

daemon.PROFILES = [Path("/tmp/empty-profile")]  # contains an empty DevToolsActivePort
daemon.get_ws_url()
# before: ValueError: not enough values to unpack (expected 2, got 1)
# after:  RuntimeError: DevToolsActivePort not found in [...] — enable chrome://inspect/#remote-debugging

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Skip malformed or empty DevToolsActivePort files during CDP discovery to prevent crashes and keep scanning for a valid profile. Also prioritize a dedicated `Chrome-CDP` profile in `PROFILES` to support headless Chrome 148+.

- **Bug Fixes**
  - Catch `ValueError` when parsing `DevToolsActivePort`; skip bad profiles and continue discovery.
  - Replaces the fatal “not enough values to unpack” with the normal “DevToolsActivePort not found — enable chrome://inspect…” guidance.

- **Docs**
  - Added `interaction-skills/headless-automation.md` (non-default `--user-data-dir`, headless port file synthesis, launcher script, launchd example).
  - New domain guides: `domain-skills/angellist/investor-portfolio.md`, `domain-skills/x.com/articles.md`, `domain-skills/x.com/bookmarks.md`.
  - Updated `SKILL.md` with a link to headless automation and two Chrome gotchas (148+ `--remote-debugging-port` restriction, `--headless=new` not writing `DevToolsActivePort`).

<sup>Written for commit 16943d9faa124d47e7bd79427c4cc9252fbf36f1. Summary will update on new commits.</sup>

<a href="https://cubic.dev/pr/browser-use/browser-harness/pull/456?utm_source=github" target="_blank" rel="noopener noreferrer" data-no-image-dialog="true"><picture><source media="(prefers-color-scheme: dark)" srcset="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"><source media="(prefers-color-scheme: light)" srcset="https://www.cubic.dev/buttons/review-in-cubic-light.svg"><img alt="Review in cubic" src="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"></picture></a>

<!-- End of auto-generated description by cubic. -->

[browser-harness-review]

✅ Skill review passed

Reviewed 5 file(s) — no findings.

[cubic-dev-ai]

1 issue found across 6 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="daemon.py">

<violation number="1" location="daemon.py:66">
P2: The `except ValueError` guard is incomplete: a two-line `DevToolsActivePort` with a non-numeric port (e.g. `abc\n/devtools/browser/...`) passes the `split()` step, then later crashes at `int(port.strip())` inside the inner `try` that only catches `OSError`. This still aborts profile fallback, defeating the PR's goal of skipping all malformed files.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>

[cubic-dev-ai]

P2: The except ValueError guard is incomplete: a two-line DevToolsActivePort with a non-numeric port (e.g. abc\n/devtools/browser/...) passes the split() step, then later crashes at int(port.strip()) inside the inner try that only catches OSError. This still aborts profile fallback, defeating the PR's goal of skipping all malformed files.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At daemon.py, line 66:

<comment>The `except ValueError` guard is incomplete: a two-line `DevToolsActivePort` with a non-numeric port (e.g. `abc\n/devtools/browser/...`) passes the `split()` step, then later crashes at `int(port.strip())` inside the inner `try` that only catches `OSError`. This still aborts profile fallback, defeating the PR's goal of skipping all malformed files.</comment>

<file context>
@@ -62,6 +63,9 @@ def get_ws_url():
             port, path = (base / "DevToolsActivePort").read_text().strip().split("\n", 1)
         except (FileNotFoundError, NotADirectoryError):
             continue
+        except ValueError:
+            # malformed/empty DevToolsActivePort (stale profile) — skip, try next
+            continue
</file context>