mirrors/hermes-agent
1
0
Fork 0
mirror of https://github.com/NousResearch/hermes-agent.git synced 2026-07-31 19:16:29 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

feat(browser): store full snapshots on truncation; make eval denylist opt-in (#65923)

Browse source 
* feat(browser): store full snapshots on truncation; make eval denylist opt-in

Two harness fixes motivated by BU_Bench results where fixed-verb + lossy
observation cost Hermes heavily vs code-driven browser agents:

1. Snapshot truncation no longer loses content. When a snapshot exceeds
   the 8000-char threshold, the complete accessibility tree is saved to
   cache/web (same truncate-and-store pattern as web_extract) and the
   truncated view / LLM summary includes the file path plus a ready-made
   read_file call. Element refs beyond the cut are recoverable without
   re-snapshotting. Stored copies are force-redacted and capped at 2MB;
   content-hash filenames dedupe repeated snapshots of the same page.

2. The browser_console(expression=...) sensitive-primitive denylist is
   now opt-in via browser.restrict_evaluate (default false). The
   names-based denylist blocked legitimate DOM extraction — any selector
   or expression containing 'fetch', 'cookie', 'input', etc. — which
   crippled the agent's only programmatic page-inspection path. The
   SSRF/private-URL egress guards in _browser_eval are independent of
   this policy and remain always-on. browser.allow_unsafe_evaluate keeps
   its meaning (bypass the denylist) for configs that already set it.

* test: update None-guard test for stored-snapshot pointer in _extract_relevant_content

test_normal_content_returned pinned the exact return value; the summary
now carries a pointer to the stored full snapshot. Assert the summary
passes through and the pointer is present instead.

* feat(browser): align snapshot threshold with web_extract's 15k char budget

SNAPSHOT_SUMMARIZE_THRESHOLD 8000 -> 15000, matching
web_tools.DEFAULT_EXTRACT_CHAR_LIMIT so the snapshot and web_extract
truncate-and-store paths give the model the same per-page budget.
_truncate_snapshot's default max_chars now follows the constant.
Invariant test added; docs (en+zh) and CLI tip updated.
This commit is contained in:
Teknium 2026-07-16 23:41:26 -07:00 • committed by GitHub
parent 779019ef7d
commit 0f102fa4dc
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
8 changed files with 262 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

6
website/docs/user-guide/features/browser.md
View file

@ -443,7 +443,7 @@ Get a text-based snapshot of the current page's accessibility tree. Returns inte
- **`full=false`** (default): Compact view showing only interactive elements
- **`full=true`**: Complete page content
Snapshots over 8000 characters are automatically summarized by an LLM.
Snapshots over 15,000 characters are automatically truncated or summarized by an LLM (the same per-page budget as `web_extract`). When that happens, the complete snapshot is saved to `~/.hermes/cache/web/` and the tool output includes the file path plus a ready-to-use `read_file` call, so the agent can page through the full accessibility tree — including element refs beyond the cut — without re-snapshotting.
### `browser_click`
@ -518,6 +518,8 @@ browser_console(expression="JSON.stringify(performance.timing)")
When a CDP supervisor is active for the current session (typical for any session that's run `browser_navigate` against a CDP-capable backend), evaluation runs over the supervisor's persistent WebSocket — no subprocess startup cost. Falls through to the standard agent-browser CLI path otherwise. Behaviour is identical either way; only latency changes.
Evaluation is unrestricted by default — the agent can use `fetch`, read storage, query form values, and run any DOM extraction. Requests targeting private/internal addresses are still blocked on non-local backends (the SSRF guard is independent of this setting). If you browse hostile pages with a logged-in profile and want a strict denylist over sensitive JS primitives (cookies, storage, clipboard, network calls, form values), opt in with `browser.restrict_evaluate: true` in `config.yaml`. Note the denylist matches primitive *names*, so it also blocks legitimate expressions that merely contain words like `fetch` or `cookie`.
### `browser_cdp`
Raw Chrome DevTools Protocol passthrough — the escape hatch for browser operations not covered by the other tools. Use for native dialog handling, iframe-scoped evaluation, cookie/network control, or any CDP verb the agent needs.
@ -655,7 +657,7 @@ If paid features aren't available on your plan, Hermes automatically falls back
## Limitations
- **Text-based interaction** — relies on accessibility tree, not pixel coordinates
- **Snapshot size** — large pages may be truncated or LLM-summarized at 8000 characters
- **Snapshot size** — large pages may be truncated or LLM-summarized at 15,000 characters (matching `web_extract`); the complete snapshot is saved to `~/.hermes/cache/web/` and the output points at it for `read_file` paging
- **Session timeout** — cloud sessions expire based on your provider's plan settings
- **Cost** — cloud sessions consume provider credits; sessions are automatically cleaned up when the conversation ends or after inactivity. Use `/browser connect` for free local browsing.
- **No file downloads** — cannot download files from the browser