Add Playwright install and usage recipe for JS-rendered APIs

[TerraFarmr]

Filed by /printing-press-retro from a run of TNSTC OTRS
(scorecard Not formally run, Build + live smoke tests passed).

Summary

When extracting JavaScript-rendered content, the agent needed to install Playwright (pip3 install playwright, python3 -m playwright install chromium) but struggled with missing guidance. The install requires --break-system-packages on Debian-based systems, and the agent didn't know whether to use expect_navigation or response interception for AJAX calls, leading to timeout errors. Providing the correct Linux install incantation and basic usage patterns would eliminate this recurring friction.

Where to look

• Component: skill
• Likely area: skills/printing-press/SKILL.md — new ## JS-rendered APIs section
• Triggered when: A portal or SPA requires JavaScript execution to render key data (e.g., seat layouts), forcing the agent to use Playwright or a similar headless browser via Python scripting.

What we observed

The agent spent significant time installing and debugging Playwright:

• First pip install failed with a Debian PEP 668 constraint (--break-system-packages missing).
• tnstc_seats.py needed ~4 rewrites because the agent incorrectly used expect_navigation instead of page.on("response", ...) interception for Struts AJAX calls.

Suspected root cause

The skill lacks guidance on secondary scripting languages (Python/Playwright) as escape valves for JS-rendered responses, leaving the agent to reason through installation and usage patterns independently.

Suggested direction

Add a ## JS-rendered APIs: Playwright recipe section covering:

1. Decision heuristic: Try pure HTTP first; fall back to Playwright only if JS-rendered.
2. Correct install on Linux root (pip3 install playwright --break-system-packages && python3 -m playwright install chromium).
3. The async/context manager pattern.
4. Response interception pattern for AJAX endpoints instead of waiting for navigation.

Acceptance criteria

• positive: Agent building a JS-rendered portal CLI installs Playwright on the first try with correct flags and uses response interception for AJAX endpoints.
• negative: The recipe is gated on JS rendering detection; normal REST CLI workflows are unaffected.

Frequency

subclass:js-rendered-portal

Complexity

small

Scope boundary

Linux/macOS only (Windows out of scope). Python Playwright only (Node.js Playwright out of scope).

Dependencies

None.

Artifacts

Artifact	Link
Retro document	Upload failed — see local copy
Manuscripts (research + proofs)	Upload failed — see local copy
Generated CLI source code	Upload failed — see local copy

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Generated by /printing-press-retro · CLI Printing Press