Cass

CASS - Coding Agent Session Search

Unified, high-performance CLI/TUI to index and search your local coding agent history. Aggregates sessions from 11 agents: Codex, Claude Code, Gemini CLI, Cline, OpenCode, Amp, Cursor, ChatGPT, Aider, Pi-Agent, and Factory (Droid).

CRITICAL: Robot Mode Required for AI Agents

NEVER run bare cass - it launches an interactive TUI that blocks your session!

# WRONG - blocks terminal
cass

# CORRECT - JSON output for agents
cass search "query" --robot
cass search "query" --json  # alias

Always use --robot or --json flags for machine-readable output.

Quick Reference for AI Agents

Pre-Flight Check

# Health check (exit 0=healthy, 1=unhealthy, <50ms)
cass health

# If unhealthy, rebuild index
cass index --full

Essential Commands

# Search with JSON output
cass search "authentication error" --robot --limit 5

# Search with metadata (elapsed_ms, cache stats, freshness)
cass search "error" --robot --robot-meta

# Minimal payload (path, line, agent only)
cass search "bug" --robot --fields minimal

# View source at specific line
cass view /path/to/session.jsonl -n 42 --json

# Expand context around a line
cass expand /path/to/session.jsonl -n 42 -C 5 --json

# Capabilities discovery
cass capabilities --json

# Full API schema
cass introspect --json

# LLM-optimized documentation
cass robot-docs guide
cass robot-docs commands
cass robot-docs schemas
cass robot-docs examples
cass robot-docs exit-codes

Why Use CASS

Cross-Agent Knowledge Transfer

Your coding agents create scattered knowledge:

• Claude Code sessions in ~/.claude/projects
• Codex sessions in ~/.codex/sessions
• Cursor state in SQLite databases
• Aider history in markdown files

CASS unifies all of this into a single searchable index. When you're stuck on a problem, search across ALL your past agent sessions to find relevant solutions.

Use Cases

# "I solved this before..."
cass search "TypeError: Cannot read property" --robot --days 30

# Cross-agent learning (what has ANY agent said about X?)
cass search "authentication" --robot --workspace /path/to/project

# Agent-to-agent handoff
cass search "database migration" --robot --fields summary

# Daily review
cass timeline --today --json

Command Reference

Indexing

# Full rebuild of DB and search index
cass index --full

# Incremental update (since last scan)
cass index

# Watch mode: auto-reindex on file changes
cass index --watch

# Force rebuild even if schema unchanged
cass index --full --force-rebuild

# Safe retries with idempotency key (24h TTL)
cass index --full --idempotency-key "build-$(date +%Y%m%d)"

# JSON output with stats
cass index --full --json

Search

# Basic search (JSON output required for agents!)
cass search "query" --robot

# With filters
cass search "error" --robot --agent claude --days 7
cass search "bug" --robot --workspace /path/to/project
cass search "panic" --robot --today

# Time filters
cass search "auth" --robot --since 2024-01-01 --until 2024-01-31
cass search "test" --robot --yesterday
cass search "fix" --robot --week

# Wildcards
cass search "auth*" --robot          # prefix: authentication, authorize
cass search "*tion" --robot          # suffix: authentication, exception
cass search "*config*" --robot       # substring: misconfigured

# Token budget management (critical for LLMs!)
cass search "error" --robot --fields minimal              # path, line, agent only
cass search "error" --robot --fields summary              # adds title, score
cass search "error" --robot --max-content-length 500      # truncate fields
cass search "error" --robot --max-tokens 2000             # soft budget (~4 chars/token)
cass search "error" --robot --limit 5                     # cap results

# Pagination (cursor-based)
cass search "TODO" --robot --robot-meta --limit 20
# Use _meta.next_cursor from response:
cass search "TODO" --robot --robot-meta --limit 20 --cursor "eyJ..."

# Match highlighting
cass search "authentication error" --robot --highlight

# Query analysis/debugging
cass search "auth*" --robot --explain    # parsed query, cost estimates
cass search "auth error" --robot --dry-run  # validate without executing

# Aggregations (server-side counts)
cass search "error" --robot --aggregate agent,workspace,date

# Request correlation
cass search "bug" --robot --request-id "req-12345"

# Source filtering (for multi-machine setups)
cass search "auth" --robot --source laptop
cass search "error" --robot --source remote

# Traceability (for debugging agent pipelines)
cass search "error" --robot --trace-file /tmp/cass-trace.json

Session Analysis

# Export conversation to markdown/HTML/JSON
cass export /path/to/session.jsonl --format markdown -o conversation.md
cass export /path/to/session.jsonl --format html -o conversation.html
cass export /path/to/session.jsonl --format json --include-tools

# Expand context around a line (from search result)
cass expand /path/to/session.jsonl -n 42 -C 5 --json
# Shows 5 messages before and after line 42

# View source at line
cass view /path/to/session.jsonl -n 42 --json

# Activity timeline
cass timeline --today --json --group-by hour
cass timeline --days 7 --json --agent claude
cass timeline --since 7d --json

# Find related sessions for a file
cass context /path/to/source.ts --json

Status & Diagnostics

# Quick health (<50ms)
cass health
cass health --json

# Full status snapshot
cass status --json
cass state --json  # alias

# Statistics
cass stats --json
cass stats --by-source  # for multi-machine

# Full diagnostics
cass diag --verbose

Aggregation & Analytics

Aggregate search results server-side to get counts and distributions without transferring full result data:

# Count results by agent
cass search "error" --robot --aggregate agent
# → { "aggregations": { "agent": { "buckets": [{"key": "claude_code", "count": 45}, ...] } } }

# Multi-field aggregation
cass search "bug" --robot --aggregate agent,workspace,date

# Combine with filters
cass search "TODO" --agent claude --robot --aggregate workspace

Top 10 buckets returned per field, with other_count for remaining items.

Remote Sources (Multi-Machine Search)

Search across sessions from multiple machines via SSH/rsync.

Setup Wizard (Recommended)

cass sources setup

The wizard:

1. Discovers SSH hosts from ~/.ssh/config
2. Probes each for agent data and cass installation
3. Optionally installs cass on remotes
4. Indexes sessions on remotes
5. Configures sources.toml
6. Syncs data locally

cass sources setup --hosts css,csd,yto  # Specific hosts only
cass sources setup --dry-run             # Preview without changes
cass sources setup --resume              # Resume interrupted setup

Manual Setup

# Add a remote machine
cass sources add user@laptop.local --preset macos-defaults
cass sources add dev@workstation --path ~/.claude/projects --path ~/.codex/sessions

# List sources
cass sources list --json

# Sync sessions
cass sources sync
cass sources sync --source laptop --verbose

# Check connectivity
cass sources doctor
cass sources doctor --source laptop --json

# Path mappings (rewrite remote paths to local)
cass sources mappings list laptop
cass sources mappings add laptop --from /home/user/projects --to /Users/me/projects
cass sources mappings test laptop /home/user/projects/myapp/src/main.rs

# Remove source
cass sources remove laptop --purge -y

Configuration stored in ~/.config/cass/sources.toml (Linux) or ~/Library/Application Support/cass/sources.toml (macOS).

Robot Mode Deep Dive

Self-Documenting API

CASS teaches agents how to use itself:

# Quick capability check
cass capabilities --json
# Returns: features, connectors, limits

# Full API schema
cass introspect --json
# Returns: all commands, arguments, response shapes

# Topic-based docs (LLM-optimized)
cass robot-docs commands   # all commands and flags
cass robot-docs schemas    # response JSON schemas
cass robot-docs examples   # copy-paste invocations
cass robot-docs exit-codes # error handling
cass robot-docs guide      # quick-start walkthrough
cass robot-docs contracts  # API versioning
cass robot-docs sources    # remote sources guide

Forgiving Syntax (Agent-Friendly)

CASS auto-corrects common mistakes:

Command Aliases:

• find, query, q, lookup, grep → search
• ls, list, info, summary → stats
• st, state → status
• reindex, idx, rebuild → index
• show, get, read → view
• docs, help-robot, robotdocs → robot-docs

Output Formats

# Pretty-printed JSON (default)
cass search "error" --robot

# Streaming JSONL (header + one hit per line)
cass search "error" --robot-format jsonl

# Compact single-line JSON
cass search "error" --robot-format compact

# With performance metadata
cass search "error" --robot --robot-meta

Design principle: stdout = JSON only; diagnostics go to stderr.

Token Budget Management

LLMs have context limits. Control output size:

Truncated fields include *_truncated: true indicator.

Structured Error Handling

Errors are JSON with actionable hints:

{
  "error": {
    "code": 3,
    "kind": "index_missing",
    "message": "Search index not found",
    "hint": "Run 'cass index --full' to build the index",
    "retryable": false
  }
}

Exit Codes

Search Modes

Three search modes, selectable with --mode flag:

cass search "authentication" --mode lexical --robot
cass search "how to handle user login" --mode semantic --robot
cass search "auth error handling" --mode hybrid --robot

Hybrid combines lexical and semantic using RRF:

RRF_score = Σ 1 / (60 + rank_i)

Pipeline Mode (Chained Search)

Chain searches by piping session paths:

# Find sessions mentioning "auth", then search within those for "token"
cass search "authentication" --robot-format sessions | \
  cass search "refresh token" --sessions-from - --robot

# Build a filtered corpus from today's work
cass search --today --robot-format sessions > today_sessions.txt
cass search "bug fix" --sessions-from today_sessions.txt --robot

Use cases:

• Drill-down: Broad search → narrow within results
• Cross-reference: Find sessions with term A, then find term B within them
• Corpus building: Save session lists for repeated searches

Query Language

Basic Queries

Boolean Operators

# Complex boolean query
cass search "authentication AND (error OR failure) NOT test" --robot

# Exclude test files
cass search "bug fix -test -spec" --robot

# Either error type
cass search "TypeError OR ValueError" --robot

Wildcard Patterns

Match Types

Results include match_type:

Auto-Fuzzy Fallback

When exact query returns <3 results, CASS automatically retries with wildcards:

• auth → *auth*
• Results flagged with wildcard_fallback: true

Flexible Time Input

CASS accepts a wide variety of time/date formats:

Ranking Modes

Cycle with F12 in TUI or use --ranking flag:

Score Components

• Text Relevance (BM25): Term frequency, inverse document frequency, length normalization
• Recency: Exponential decay (today ~1.0, last week ~0.7, last month ~0.3)
• Match Exactness: Exact phrase=1.0, Prefix=0.9, Suffix=0.8, Substring=0.6, Fuzzy=0.4

Blended Scoring Formula

Final_Score = BM25_Score × Match_Quality + α × Recency_Factor

Supported Agents (11 Connectors)

Note: ChatGPT v2/v3 are AES-256-GCM encrypted (keychain access required). Legacy v1 unencrypted conversations are indexed automatically.

TUI Features (for Humans)

Launch with cass (no flags):

Keyboard Shortcuts

Navigation:

• Up/Down: Move selection
• Left/Right: Switch panes
• Tab/Shift+Tab: Cycle focus
• Enter: Open in $EDITOR
• Space: Full-screen detail view
• Home/End: Jump to first/last result
• PageUp/PageDown: Scroll by page

Filtering:

• F3: Agent filter
• F4: Workspace filter
• F5/F6: Time filters (from/to)
• Shift+F3: Scope to current result's agent
• Shift+F4: Clear workspace filter
• Shift+F5: Cycle presets (24h/7d/30d/all)
• Ctrl+Del: Clear all filters

Modes:

• F2: Toggle theme (6 presets)
• F7: Context window size (S/M/L/XL)
• F9: Match mode (prefix/standard)
• F12: Ranking mode
• Ctrl+B: Toggle border style

Selection & Actions:

• m: Toggle selection
• Ctrl+A: Select all
• A: Bulk actions menu
• Ctrl+Enter: Add to queue
• Ctrl+O: Open all queued
• y: Copy path/content
• Ctrl+Y: Copy all selected
• /: Find in detail pane
• n/N: Next/prev match

Views & Palette:

• Ctrl+P: Command palette
• 1-9: Load saved view
• Shift+1-9: Save view to slot

Source Filtering (multi-machine):

• F11: Cycle source filter (all/local/remote)
• Shift+F11: Source selection menu

Global:

• Ctrl+C: Quit
• F1 or ?: Toggle help
• Ctrl+Shift+R: Force re-index
• Ctrl+Shift+Del: Reset all TUI state

Detail Pane Tabs

Context Window Sizing

Peek Mode (Ctrl+Space): Temporarily expand to XL without changing default.

Theme Presets

Cycle through 6 built-in themes with F2:

All themes validated against WCAG contrast requirements (4.5:1 minimum for text).

Role-Aware Message Styling

Saved Views

Save filter configurations to 9 slots for instant recall.

What Gets Saved:

• Active filters (agent, workspace, time range)
• Current ranking mode
• The search query

Keyboard:

• Shift+1 through Shift+9: Save current view
• 1 through 9: Load view from slot

Via Command Palette: Ctrl+P → "Save/Load view"

Views persist in tui_state.json across sessions.

Density Modes

Control lines per search result. Cycle with Shift+D:

Bookmark System

Save important results with notes and tags:

In TUI: Press b to bookmark, add notes and tags.

Bookmark Structure:

• title: Short description
• source_path, line_number, agent, workspace
• note: Your annotations
• tags: Comma-separated labels
• snippet: Extracted content

Storage: ~/.local/share/coding-agent-search/bookmarks.db (SQLite)

Optional Semantic Search

Local-only semantic search using MiniLM (no cloud):

Required files (place in data directory):

• model.onnx
• tokenizer.json
• config.json
• special_tokens_map.json
• tokenizer_config.json

Vector index stored as vector_index/index-minilm-384.cvvi.

CASS does NOT auto-download models; you must manually install them.

Hash Embedder Fallback: When MiniLM not installed, CASS uses a hash-based embedder for approximate semantic similarity.

Watch Mode

Real-time index updates:

cass index --watch

• Debounce: 2 seconds (wait for burst to settle)
• Max wait: 5 seconds (force flush during continuous activity)
• Incremental: Only re-scans modified files

TUI automatically starts watch mode in background.

Deduplication Strategy

CASS uses multi-layer deduplication:

1. Message Hash: SHA-256 of (role + content + timestamp) - identical messages stored once
2. Conversation Fingerprint: Hash of first N message hashes - detects duplicate files
3. Search-Time Dedup: Results deduplicated by content similarity

Noise Filtering:

• Empty messages and pure whitespace
• System prompts (unless searching for them)
• Repeated tool acknowledgments

Performance Characteristics

Memory: 70-140MB typical (50K messages) Disk: ~600 bytes/message (including n-gram overhead)

Response Shapes

Search Response:

{
  "query": "error",
  "limit": 10,
  "count": 5,
  "total_matches": 42,
  "hits": [
    {
      "source_path": "/path/to/session.jsonl",
      "line_number": 123,
      "agent": "claude_code",
      "workspace": "/projects/myapp",
      "title": "Authentication debugging",
      "snippet": "The error occurs when...",
      "score": 0.85,
      "match_type": "exact",
      "created_at": "2024-01-15T10:30:00Z"
    }
  ],
  "_meta": {
    "elapsed_ms": 12,
    "cache_hit": true,
    "wildcard_fallback": false,
    "next_cursor": "eyJ...",
    "index_freshness": { "stale": false, "age_seconds": 120 }
  }
}

Aggregation Response:

{
  "aggregations": {
    "agent": {
      "buckets": [
        {"key": "claude_code", "count": 120},
        {"key": "codex", "count": 85}
      ],
      "other_count": 15
    }
  }
}

Environment Variables

Shell Completions

cass completions bash > ~/.local/share/bash-completion/completions/cass
cass completions zsh > "${fpath[1]}/_cass"
cass completions fish > ~/.config/fish/completions/cass.fish
cass completions powershell >> $PROFILE

API Contract & Versioning

cass api-version --json
# → { "version": "0.4.0", "contract_version": "1", "breaking_changes": [] }

cass introspect --json
# → Full schema: all commands, arguments, response types

Guaranteed Stable:

• Exit codes and their meanings
• JSON response structure for --robot output
• Flag names and behaviors
• _meta block format

Integration with CASS Memory (cm)

CASS provides episodic memory (raw sessions). CM extracts procedural memory (rules and playbooks):

# 1. CASS indexes raw sessions
cass index --full

# 2. Search for relevant past experience
cass search "authentication timeout" --robot --limit 10

# 3. CM reflects on sessions to extract rules
cm reflect

Troubleshooting

Installation

# One-liner install
curl -fsSL https://raw.githubusercontent.com/Dicklesworthstone/coding_agent_session_search/main/install.sh \
  | bash -s -- --easy-mode --verify

# Windows
irm https://raw.githubusercontent.com/Dicklesworthstone/coding_agent_session_search/main/install.ps1 | iex

Integration with Flywheel