# Roadmap

This document outlines the major decisions, milestones, and development phases required to bring `tai` from concept to a working tool.

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## Phase 0 — Decisions & Prerequisites

These must be resolved before meaningful development can begin.

### Language Selection

- [x] **Decision: Python**
- Key factors: native vLLM integration, mature SSH libraries (`paramiko` / `asyncssh`), strong text/log parsing, rapid development
- Single binary distribution will be achieved via **Nuitka** (preferred for true compilation) or **PyInstaller** as a fallback
- [ ] Evaluate Nuitka vs PyInstaller for binary output quality and CI reproducibility
- [ ] Add binary build step to CI pipeline

### AI Backend & Model

- [x] OpenAI-compatible backend client implemented (`AIClient`)
- [x] Default local backend profile wired for Ollama (`http://localhost:11434/v1`)
- [x] Default model profile set to `gemma3:4b` (override via `--model`)
- [ ] Define minimum hardware requirements for running the model locally
- [x] AI backend is user-supplied/self-hosted

### SSH Strategy

- [x] **Decision: keypair authentication only** — no password auth; eliminates credential storage risk
  - Default key resolution: `~/.ssh/id_ed25519`, `~/.ssh/id_rsa` (in order of preference)
  - CLI override via `--identity-file <path>`
  - No SSH agent forwarding needed — a shared key is distributed to all managed hosts via Puppet
- [x] **Known hosts: auto-accept new hosts; reject on key mismatch** — a changed host key triggers a hard stop with a MITM warning; unknown/new hosts are accepted silently on first connect
- [x] **Bastion/jump host: `--jump-host <host>` flag** — delegates to SSH's native ProxyJump functionality
- [x] **SSH config behavior: respect existing `~/.ssh/config` by default; allow CLI override**
  - Default: follow host settings from `~/.ssh/config` (for `User`, `Port`, `ProxyJump`, etc.)
  - Override switch: `--ignore-ssh-config` to bypass local SSH config when required

### Scope & Constraints

- [ ] Define the supported scope of issues (services, network, disk, kernel, etc.)
- [x] Read-only guarantee implemented with command allowlist + blocked shell operator policy
- [x] **Decision: interactive REPL mode for v0.1, full TUI for v0.2+**
  - v0.1: chat-loop REPL launched from CLI; human can follow up, correct, and redirect the agent
  - v0.2+: `textual`-based TUI with split panes (collected data | AI output | input bar)
  - Built-in slash commands: `/collect`, `/show logs`, `/clear`, `/host <hostname>`, `/help`, `/quit`

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## Phase 1 — Project Foundation

Basic project scaffolding and connectivity.

- [x] Finalise repository structure and language toolchain
- [x] Set up CI pipeline (linting, tests)
- [x] Implement SSH connection module
  - [x] Define SSH config model and probe interface scaffold
  - [x] Connect to remote host
  - [x] Execute read-only commands (e.g. `journalctl`, `systemctl status`, `cat`)
  - [x] Stream or collect command output safely (byte-limited output with truncation marker)
- [x] Implement basic input parsing (ticket text, hostname, target directories)
- [x] Write unit tests for SSH and input modules
  - [x] Input parser and CLI tests added
  - [x] SSH module tests added for command policy and SSH argv behavior

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## Phase 2 — Data Collection Layer

Define what information the agent gathers and how.

- [x] Identify a baseline canonical set of data sources per issue type:
  - Service failures: `journalctl`, `systemctl`, service config files
  - Network issues: `ip`, `ss`, `netstat`, firewall rules
  - Disk issues: `df`, `du`, `dmesg`, `smartctl`
  - General: `/var/log/syslog`, `/var/log/messages`, `dmesg`
- [x] Implement collectors and plan builder for baseline issue categories
- [x] Implement directory traversal for user-specified paths (read-only)
- [ ] Add support for per-distro variations (Ubuntu vs RHEL path differences, etc.)
- [x] Write tests with mocked SSH output

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## Phase 3 — AI Integration

Wire collected data into the local AI model.

- [x] Implement OpenAI-compatible AI client module
- [x] Design prompt templates for initial and follow-up analysis
- [x] Implement response guardrail checks and structured response headings
- [x] Tune context usage with RAG retrieval and chunk/runbook truncation budgets
- [x] Implement reliable non-streaming completion path for local backends
- [ ] Continue output quality tuning and grounding evaluation on real hosts

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## Phase 4 — CLI & User Experience

Polish the interface for real-world use.

- [x] Design CLI interface with run command, interactive prompts, and runbook subcommands
- [x] Implement structured output sections (Root Cause, Evidence, Recommended Actions)
- [x] Add RAG debug mode (`--rag-debug`) showing retrieval scores
- [ ] Support output to file or clipboard
- [x] Provide comprehensive `--help` command documentation via Typer options

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## Phase 5 — Hardening & Distribution

Prepare for broader use.

- [ ] Security review of SSH handling and credential storage
- [ ] Ensure no data is written to the remote system under any path
- [ ] Package for distribution (binary release, container image, or distro packages)
- [ ] Write installation and quickstart documentation
- [ ] End-to-end integration tests against a test VM

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## Phase 6 — RAG & Knowledge Layer

Introduce Retrieval-Augmented Generation to ground AI responses in evidence rather than
model weights alone. Three tiers of increasing capability, each buildable independently.

### Goals

- Eliminate prompt flooding on hosts with large log output
- Ground recommendations in version-controlled runbooks, not model improvisation
- Build compounding institutional memory from past troubleshooting sessions
- Keep all data local — no embeddings or session content leaves the network

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### Technology Decisions Required

| Decision | Options | Recommendation | Status |
|---|---|---|---|
| Embedding model | `nomic-embed-text`, `mxbai-embed-large`, `all-minilm` | `nomic-embed-text` via Ollama (local, 274MB, strong perf) | ✅ Implemented |
| Vector store — Tier 1 | In-memory numpy cosine, `faiss-cpu` | numpy (zero deps) for session scope | ✅ Implemented |
| Vector store — Tier 2/3 | `chromadb`, `qdrant`, `weaviate`, `pgvector` | `chromadb` embedded mode | ✅ Tier 2 Implemented |
| Chunking strategy | Fixed token, sentence-aware, command-boundary | Command-boundary splitting (natural unit for diagnostics) | ✅ Implemented |
| Hybrid retrieval | Semantic only, BM25 only, hybrid | Hybrid (BM25 keyword + cosine semantic) for best recall | ⬜ Pending |
| Reranking | None, cross-encoder (`ms-marco-MiniLM`), LLM-as-judge | Cross-encoder rerank pass before prompt injection | ⬜ Pending |
| Runbook format | Markdown, YAML, JSON | Markdown (human-editable, version-controllable) | ✅ Implemented |
| Session index storage | Local `~/.tai/`, configurable path | `~/.tai/sessions/` with ChromaDB collection | ⬜ Pending |

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### Tier 1 — Diagnostic Chunk Retrieval (in-memory, per-session)

Status: ✅ Implemented

**Problem:** Current flow injects all collected output into the prompt as one block.
On busy hosts this floods the context window with irrelevant output, degrading quality.

**Approach:**

- After collection, split each command's output into overlapping token chunks (e.g. 512 tokens, 64 overlap)
- Embed all chunks using `nomic-embed-text` via Ollama embeddings API
- On each question (initial + follow-up), embed the question and retrieve top-k chunks by cosine similarity
- Inject only retrieved chunks into the prompt, not the full dump

**New module:** `src/tai/rag_retriever.py`

- `chunk_report(report) -> list[Chunk]`
- `embed_chunks(chunks) -> list[EmbeddedChunk]`
- `retrieve(question, embedded_chunks, top_k) -> list[Chunk]`

**Changes to existing code:**

- `prompt_builder.py`: accept `retrieved_chunks` instead of full `CollectionReport` for RAG-mode prompts
- `cli.py`: embed report after collection, pass retriever to `_run_analysis` and `_run_followup_analysis`
- `ai_client.py`: add `embed(text) -> list[float]` method using Ollama `/api/embeddings`

**Companion features buildable at same time:**

- `--no-rag` flag to bypass retrieval and use full dump (backwards compat)
- Token budget display: show user how many tokens are being sent vs. saved
- Per-chunk source attribution in AI response (which command produced the evidence)

**Tests:**

- `tests/test_rag_retriever.py`: chunk splitting, cosine similarity ranking, top-k retrieval
- `tests/test_ai.py`: add `test_embed_returns_float_list()`

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### Tier 2 — Runbook Knowledge Base (persistent, ChromaDB)

Status: ✅ Implemented

**Problem:** AI improvises remediation steps from training data, which may be wrong for
specific environments, distros, or internal conventions.

**Approach:**

- Maintain a version-controlled corpus of Markdown runbooks in `runbooks/` directory
- On first run (or `tai runbooks --sync`), embed all runbooks and persist to ChromaDB collection
- On each analysis, retrieve top-3 relevant runbook chunks alongside diagnostic chunks
- Inject as a separate `## Runbook Context` section in the prompt

**New module:** `src/tai/runbook_store.py`

- `RunbookStore`: wraps ChromaDB collection
- `sync(runbooks_dir) -> int` — embed and upsert all runbooks
- `query(question, top_k) -> list[RunbookChunk]`

**New directory:** `runbooks/`

- `ssh.md`, `nginx.md`, `postgres.md`, `disk.md`, `kernel.md`, etc.
- Each runbook: YAML frontmatter (`service`, `symptoms`, `tags`) + Markdown body

**New CLI command:** `tai runbooks --sync [--path ./runbooks]`

**Changes to existing code:**

- `prompt_builder.py`: add `build_message_with_runbooks(retrieved_chunks, runbook_chunks)`
- `cli.py`: optionally load `RunbookStore`, query it per analysis turn

**Companion features buildable at same time:**

- `tai runbooks --list` — show indexed runbooks and last sync time
- `tai runbooks --add <file>` — index a single runbook
- `/runbooks` slash command in interactive mode — show which runbooks were retrieved
- Runbook citation in AI output: "Based on runbook: `ssh.md#AuthenticationFailures`"

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### Tier 3 — Session Memory Index (institutional learning)

Status: ⬜ Pending

**Problem:** Every session starts from zero. Repeat incidents on the same host or
same issue type get no benefit from past work.

**Approach:**

- On session end, embed the session summary (issue + root cause + actions) and upsert into a persistent ChromaDB collection (`~/.tai/sessions/`)
- On session start, query for similar past sessions by issue text + hostname
- Inject top-2 past sessions as `## Prior Sessions` context
- Optionally: `/history` command in interactive mode to surface past sessions explicitly

**New module:** `src/tai/session_store.py`

- `SessionStore`: wraps ChromaDB collection at `~/.tai/sessions/`
- `index_session(session_log_path)` — embed and store completed session
- `query_similar(issue, host, top_k) -> list[PastSession]`

**Changes to existing code:**

- `session_log.py`: add `summarise() -> str` method (issue + final AI response)
- `cli.py`: query `SessionStore` at session start, index at session end

**Companion features buildable at same time:**

- `tai history` CLI subcommand — search past sessions by keyword
- `tai history --host <hostname>` — all sessions for a host
- `tai history --export <file>` — export session summaries as Markdown report
- Auto-suggest: "Similar issue found from 2 weeks ago — load context? [y/N]"

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### Implementation Order

```
Tier 1 (diagnostic chunks)     ← Start here. Zero new infra. Immediate prompt quality gain.
       ↓
Tier 2 (runbook KB)            ← After Tier 1. Requires ChromaDB dep + runbook authoring.
       ↓
Tier 3 (session memory)        ← Builds on Tier 2 infrastructure. Minimal extra work.
```

**Estimated effort:**

- Tier 1: 2–3 days (new module + prompt builder changes + tests)
- Tier 2: 3–4 days (ChromaDB + runbook authoring + CLI command + tests)
- Tier 3: 1–2 days (reuses Tier 2 infrastructure)

### New Dependencies

```
# Tier 1 (zero new runtime deps — uses Ollama HTTP API already in use)
# No additions needed

# Tier 2 + 3
chromadb>=0.5,<1.0          # embedded vector store, no separate server
# OR
qdrant-client>=1.9,<2.0     # if self-hosted Qdrant preferred

sentence-transformers>=3.0  # optional: cross-encoder reranking
```

### New pyproject.toml optional group

```toml
[project.optional-dependencies]
rag = [
  "chromadb>=0.5,<1.0",
  "sentence-transformers>=3.0,<4.0",
]
```

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## Decisions Log

| Date | Decision | Outcome |
|------|----------|---------|
| 2026-05-04 | Implementation language | Python — with single distributable binary via Nuitka |
| — | AI inference backend | vLLM (provisional) |
| — | Default model | `gemma4:a4b` (provisional) |
| 2026-05-04 | SSH auth methods | Keypair only (ed25519/RSA); auto-accept new hosts; reject on key change (MITM) |
| 2026-05-04 | Bastion host support | `--jump-host` flag via SSH native ProxyJump |
| 2026-05-04 | SSH config behavior | Use `~/.ssh/config` by default; allow override via `--ignore-ssh-config` |
| 2026-05-04 | CLI vs interactive mode | Interactive: REPL for v0.1, `textual` TUI for v0.2+ |
| 2026-05-04 | RAG embedding model | `nomic-embed-text` via Ollama (local, air-gapped safe) — ⬜ pending confirmation |
| 2026-05-04 | RAG vector store (Tier 1) | In-memory numpy cosine similarity — zero deps, session-scoped |
| 2026-05-04 | RAG vector store (Tier 2/3) | `chromadb` embedded mode (default) or `qdrant` self-hosted — ⬜ pending confirmation |
| 2026-05-04 | RAG chunking unit | Command-boundary splitting — each collected command = one or more chunks |
| 2026-05-04 | Runbook format | Markdown with YAML frontmatter, version-controlled in `runbooks/` directory |