feat: add network wait subcommand for request-specific sync

[mvanhorn]

Summary

• Add network wait <url-pattern> subcommand that waits for a network response matching a URL substring pattern
• Support --status <code>, --method <method>, and --timeout <ms> filters
• Reuse existing CDP Network.responseReceived event subscription (same pattern as handle_responsebody)
• Include changeset, help text, and README updates

Motivation

AI agents need to wait for specific API responses before proceeding. Currently the only synchronization is wait --load networkidle, which waits for ALL network activity to stop. For SPAs where background polling keeps the network active, networkidle never resolves or resolves at the wrong time.

Playwright has page.waitForResponse(urlPattern) for this - agent-browser has no equivalent.

Evidence

Source	Evidence	Signal
#555	network requests doesn't capture document navigations - agents can't inspect what loaded	Open issue
PR #847	Network idle detection fix for cached pages - active work on network sync	Merged
PR #464	"network response + dump" proposed but closed (scope too broad)	Closed
Reddit r/mcp	AI browser tool benchmarking - sync overhead matters for cost	10 upvotes

Usage

# Wait for any response matching a URL pattern
agent-browser network wait "/api/users"

# Wait for a specific status code
agent-browser network wait "/api/login" --status 200

# With method filter
agent-browser network wait "/api/orders" --method POST

# With custom timeout (default: 30s)
agent-browser network wait "/api/data" --timeout 10000

Text output: Matched: POST /api/login -> 200 (xhr)

JSON output: {"url":"https://example.com/api/login","method":"POST","status":200,"resourceType":"xhr"}

Technical notes

• The implementation subscribes to CDP Network.responseReceived events via mgr.client.subscribe(), matching the exact pattern used by handle_responsebody (line ~4133)
• Enables Network.enable if request tracking isn't already active
• URL matching uses substring contains (consistent with network requests --filter)
• Method extraction reads from the response's :method request header
• ~170 lines of Rust + docs

This contribution was developed with AI assistance (Claude Code).

[vercel]

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[ctate]

Thanks for this! Waiting for specific network responses is a much-needed improvement over networkidle — nice work.

Two things to fix: First, the pretty text output (Matched: POST /api/login -> 200 (xhr)) never actually displays — the generic URL handler in output.rs catches it first. Moving the network_wait check above line 152 should do it. Second, the --follow flag for console/errors is parsed and documented here but the backend doesn't implement it — best to pull that out into its own PR.

[mvanhorn]

Fixed in 4f5a6d5: moved the network_wait output check above the generic URL handler in output.rs so the pretty text displays correctly. Also removed the --follow flag parsing and docs from this PR - that's in #867.

[mvanhorn]

Both fixed in 4f5a6d5:

1. Moved network_wait check above the generic URL handler so the pretty output displays correctly
2. Removed the --follow flag code that leaked from feat: add --follow flag to console and errors commands #867

[mvanhorn]

Hey @ctate, wanted to check in on my open PRs. Quick summary:

Feedback addressed:

• feat: add network wait subcommand for request-specific sync #866 - both fixes in 4f5a6d5 (output ordering + removed leaked --follow code)
• feat: add --ignore-default-args to exclude Chrome launch flags #862 - both issues fixed in c16913f + added unit tests
• feat: add --follow flag to console and errors commands #867 - -f restored in bdcd7c7 after your refactor: make --full/-f a command-level flag instead of global #876 scoped --full to screenshots

Ready for first review:

• feat: add assert commands for test assertions with exit codes #944 / feat: return errors for missing/zero-dimension elements in selector screenshots #942 - clean resubmissions of feat: add assert commands for test assertions with exit codes #940/feat: add element screenshot error handling for selector clipping #939
• feat(dashboard): add timing and size columns to network panel #1057 - timing/size columns for network panel
• feat(cli): add --tab flag for tab-scoped commands #883, feat(cli): add network response subcommand for body capture #882, feat(cli): add media commands for audio/video playback control #880 - CLI subcommands (tab, network response, media)

No rush on any of these. Let me know if you'd prefer I consolidate or split any of them differently.