browser4-experience

name	browser4-experience
title	Progressive Experience Memory — Learning from Past Tasks
description	Use experience_save to persist task traces, experience_query to recall them on revisit, and experience_list to inspect stored knowledge. Reuses selectors, extraction patterns, and blocker awareness across sessions.
allowed-tools	Bash(browser4-cli:*)
tier	decision

Progressive Experience Memory (PEM)

The PEM system makes Browser4 progressively smarter: each successfully completed task deposits reusable knowledge so that future tasks — identical, similar, or on similar sites — complete faster with fewer steps.

1. Core Loop

Before task ──▶ experience_query ──▶ Get stored selectors, steps, blockers
    │                                      │
    ▼                                      ▼
Execute task                        P1: Replay directly
    │                               P2: Verify then replay
    ▼                               P3: Hint mode (verify all)
After task  ──▶ experience_save ──▶ P4: Advisory only
                                      P5: Cold start (no knowledge)

Copy-Paste Template

The experience tools are MCP tools called by the agent during browser4-cli agent run. The agent should call them as part of its tool set:

# Before starting a task — the agent calls experience_query to check prior knowledge
# After completing a task — the agent calls experience_save to persist what it learned
browser4-cli agent run "Go to https://amazon.com/dp/test and extract product details"

# To inspect stored knowledge, the agent calls experience_list
browser4-cli agent run "List experience knowledge entries for amazon"

2. Decision Tree

Starting a new task?
├─ experience_query returns P1 (confidence ≥ 0.85)?
│  → Replay stored steps directly. Selectors verified by existence check only.
├─ experience_query returns P2 (confidence 0.60–0.84)?
│  → Use stored selectors as primary candidates. Verify each before use.
├─ experience_query returns P3 (confidence 0.40–0.59)?
│  → Use stored knowledge as hints. Run full discovery for any failed selector.
├─ experience_query returns P4/P5 (confidence < 0.40, or cold start)?
│  → Full discovery mode. Run htmlsnapshot inspect, discover selectors fresh.
│  → Call experience_save after success to bootstrap knowledge.
└─ Always call experience_save after task completion (success or failure).
   → Success path: stores selectors, steps, extraction patterns.
   → Failure path: records negative evidence (what broke, why).

3. Retrieval Tiers

Tier	Confidence	Behavior
P1 Direct replay	≥ 0.85	Steps executed without verification. Selectors used as-is.
P2 Verify-before-replay	0.60–0.84	Each selector validated via htmlsnapshot get before use.
P3 Hint mode	0.40–0.59	Playbook provides suggestions but full discovery runs.
P4 Advisory	< 0.40	Knowledge surfaced as suggestion only. Full discovery required.
P5 Cold start	No data	No prior knowledge. Full exploration.

4. Tool Reference

experience_save

Persists a task execution trace to the knowledge store.

Argument	Required	Description
url	Yes	The URL the task operated on
trace	Yes	JSON-encoded ExecutionTrace (steps, selectors, extraction results)
outcome	No	"success" (default) or "failure"
task_type	No	One of the 12 canonical task types (e.g., extract_product_list)
intent	No	Free-text description of what the task was trying to do

Success path: Knowledge promoted with initial confidence 0.50. Subsequent verified successes raise confidence. Failure path: Negative evidence recorded. Failed selectors added to anti-patterns. Blocker awareness updated.

experience_query

Queries stored knowledge before starting a task.

Argument	Required	Description
url	Yes	The target URL
intent	No	Free-text intent description
task_type	No	Filter to a specific task type

Returns: JSON with tier, confidence, primary_selectors, extraction_query, known_blockers, warnings, steps.

experience_list

Lists stored knowledge entries (diagnostic/debug tool).

Argument	Required	Description
filter	No	Filter by domain (partial match)
task_type	No	Filter by task type
page	No	Page number (default 1)
page_size	No	Results per page (default 20, max 100)

5. Critical Warnings

Warning: Phase 1 (MVP) requires the agent to explicitly call experience_save after task completion. The automatic engine hook (onTaskComplete) is Phase 2+. Forgetting to save means knowledge is lost.

Warning: experience_query before open_session is supported — it operates on the file system, not the browser. Use it to plan your task before launching Chrome.

Warning: Knowledge stored for one URL pattern (e.g., /dp/*) is not automatically available for a different pattern (e.g., /s?k=*). The query matches by URL pattern specificity.

Note: The knowledge store is file-backed YAML under knowledge/ in the agent data directory. It is safe to version with git. Traces (under knowledge/.traces/) are ephemeral (30-day TTL) and not versioned.

6. Knowledge Store Layout

knowledge/
├── sites/<domain>.yaml       — One file per domain (L1–L3 knowledge)
├── .index.yaml               — In-memory index, materialized on write
├── .traces/<domain>/          — Raw execution traces (30-day TTL)
├── .archive/                  — Evicted artifacts (recoverable)
└── .wal/<domain>.log          — Write-ahead log (Phase 5+)

7. Reference Map

• Design document — Full architecture and implementation guide
• Proposal (v2) — 2300-line technical design
• CLAUDE.md — Project context and conventions