corpus-loom 0.3.3

CorpusLoom: chunking, retrieval, JSON-mode, and a CLI (cloom) for Ollama

CorpusLoom

Python SDK + CLI for local LLM workflows on Ollama.
Ingest and embed documents into a corpus, retrieve top-K context (RAG), template prompts, persist chat history, and enforce strict JSON/typed outputs — all locally, privacy-first. The CLI is cloom.

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Table of contents

1. Install
2. Quick start
3. Core concepts
4. Modes
   • Generation
   • Chat
   • JSON mode (schema-enforced)
   • Ingest & Retrieval (RAG)
5. Re-ingest strategies & incremental updates
6. Model options (behavior tuning)
7. CLI usage (cloom)
8. Recipes
9. Templating
10. Streaming
11. Performance & scaling tips
12. Tests, coverage, and CI
13. Troubleshooting
14. FAQ

---

Install

Requirements:

• Python 3.9+
• Ollama running locally (default: http://localhost:11434)
• The model(s) you want pulled, e.g.:

  ollama pull gpt-oss:20b
  ollama pull nomic-embed-text
  

Install the package (and optional extras):

pip install -e .            # local dev install (installs the 'cloom' CLI)
pip install -e ".[json]"    # add Pydantic for JSON-mode validation (recommended)
pip install -e ".[dev]"     # dev tools: pytest, ruff, mypy, coverage

---

Quick start

Python

from typing import List
from pydantic import BaseModel, Field
from corpusloom import OllamaClient

# Initialize the client
client = OllamaClient(
    model="gpt-oss:20b",
    host="http://localhost:11434",
    keep_alive="10m",                 # keep model warm
    default_options={"temperature": 0.2, "num_ctx": 16384},  # generation defaults
)

# 1) Ingest documents into your corpus
client.add_files(["docs/**/*.md", "specs/*.txt"])  # chunk + embed + store

# 2) Build a context block via similarity search (RAG)
ctx = client.build_context("overshoot < 5% controller threshold", top_k=5)

# 3) Generate using that context
res = client.generate(f"Using this context, outline tests:\n{ctx}")
print(res.response_text)

# 4) Enforce structured JSON with Pydantic
class Plan(BaseModel):
    requirement_id: str
    overview: str
    cases: List[str] = Field(default_factory=list)

plan = client.generate_json(
    prompt="Create a Plan for Use Case from this context:\n" + ctx,
    schema=Plan,   # validated; auto-repair loop on validation error
)
print(plan)

CLI

# Ingest
cloom ingest docs/**/*.md --strategy auto

# Retrieve & stitch a context block
cloom context "overshoot < 5%" --top-k 6 > ctx.md

# Single-shot generation
cloom generate --prompt-file prompt.txt --opt temperature=0.2

# Chat with state
cloom chat new --system "Be concise."
cloom chat send --convo-id <UUID> --message "Draft test cases" --stream

# JSON-only output
cloom json --prompt 'Return ONLY a JSON object with fields a, b'

---

Core concepts

• Corpus → Documents → Chunks → Embeddings → Index → Retrieval
  • Corpus: your total body of reference content.
  • Document: a single logical item (file, page), stored with metadata.
  • Chunk: a slice of a document sized for the model (default ≈ 800 tokens, ~120 overlap).
  • Embedding: a vector for each chunk (default embed model: nomic-embed-text).
  • Index/store: persisted in SQLite; used to retrieve relevant chunks.
  • Retrieval: cosine similarity search; stitch top-K chunks into a context block.

---

Modes

Generation

Single-shot text completion via Ollama’s /api/generate.

res = client.generate("Write a haiku about communication control.")
print(res.response_text)

• Streaming: client.generate(..., stream=True) yields tokens as they arrive.
• Options: pass options={...} per call or set default_options at init.

---

Chat

Multi-turn conversations via /api/chat. History is persisted.

cid = client.new_conversation(system="Be concise and cite standards when relevant.")
r1 = client.chat(cid, "Draft test for Use-Case-045.")
r2 = client.chat(cid, "Add fuzzing strategies for sensor noise.")
print(r2.reply.content)

# Inspect conversation:
for msg in client.history(cid):
    print(msg.role, ">>", msg.content[:120])

Use chat when you need iterative refinement with retained context.

---

JSON mode (schema-enforced)

Produce strict JSON that must validate against a Pydantic model (v1 or v2).
If validation fails, a repair loop is auto-prompted (bounded retries).

from typing import List
from pydantic import BaseModel, Field

class Case(BaseModel):
    id: str
    title: str
    steps: List[str]
    expected: List[str]

class Plan(BaseModel):
    requirement_id: str
    overview: str
    cases: List[TestCase] = Field(default_factory=list)

obj = client.generate_json(
    "Create a plan for Use-Case-045 from the context below:\n" + ctx,
    schema=Plan,
    # options={"temperature": 0.0},  # default forced to 0.0 for JSON mode
)

Under the hood, we apply a strict “JSON-only” system message, extract a valid JSON block, and validate it with Pydantic. You can also use the server-side format="json" option (see Model options).

---

Ingest & Retrieval (RAG)

Ingest: chunk + embed + store documents.

client.add_files(
    ["docs/**/*.md", "src/**/*.py"],
    strategy="auto",                 # auto | replace | skip
)
# or raw text:
doc_id, chunk_ids = client.add_text(big_text_blob, source="inline")

Retrieve: rank by cosine similarity and stitch a context block.

ctx = client.build_context("PID overshoot tests", top_k=6)
res = client.generate(f"Using this context, propose 5 robust tests:\n{ctx}")

---

Re-ingest strategies & incremental updates

add_files(..., strategy="auto" | "replace" | "skip")

• auto (default): if file unchanged (content hash) → skip. If changed → delete prior chunks under the same doc id and rebuild (embedding cache prevents re-embedding identical text).
• replace: always rebuild the doc’s chunks (even if unchanged).
• skip: if any doc exists for that source path → skip (even if changed).

Advanced: add_text(..., doc_id=<existing>, reuse_incremental=True) will insert only new/changed chunks keyed by a chunk_hash, keeping identical ones.

---

Model options (behavior tuning)

You can pass options at init via default_options={...} or per call via options={...}.
These map to Ollama’s generation parameters. Availability can vary by model.

Option	What it controls	Typical range / notes
num_ctx	Context window size (tokens)	2048–32768 (model-dependent); larger lets you stuff more context
num_predict	Max new tokens to generate	64–4096; -1 unlimited; -2 fill to context
temperature	Creativity vs determinism	0.0–1.2; lower = focused, higher = diverse
top_k	Sample from top-K candidates	20–100; lower = safer, higher = varied
top_p	Nucleus sampling threshold	0.7–0.97; keep minimal set reaching probability p
min_p	Minimum prob cutoff (alt to top_p)	0.01–0.1
repeat_penalty	Repetition penalty	1.05–1.5; higher reduces repeats
repeat_last_n	Window for repeat penalty	64–2048; 0 disables, -1 full num_ctx
tfs_z	Tail-free sampling	1 (off) – 2
mirostat	Mirostat perplexity control	0 off, 1 v1, 2 v2
mirostat_eta	Mirostat learning rate	~0.1
mirostat_tau	Mirostat target surprise	~5.0
seed	Random seed	Fix for reproducible outputs
stop	Stop sequences	List of strings to halt generation
format="json"	Server-side JSON enforcement	Useful for structured outputs (pairs well with Pydantic)
system	System prompt (chat)	Global instructions/role
template	Model prompt template override	Advanced; model-specific
suffix	Text appended after model response	Code completion scenarios
raw	Disable template formatting	Send your prompt as-is
context	Continue from prior /generate	Token array returned by Ollama
keep_alive	Keep model loaded post-call	e.g. "10m"; 0 to unload

Practical presets

• Factual/terse: temperature=0.1, top_p=0.9, repeat_penalty=1.1
• Creative: temperature=0.8, top_p=0.95, top_k=100
• Strict JSON: temperature=0.0 (also enable format="json" if the model supports it)
• Fast debug: num_predict=200, temperature=0.2

---

CLI usage (cloom)

The CLI mirrors the Python API. Generation options are passed via repeated --opt key=value or a JSON blob via --opts-json.

Common global flags:

• --model (default: gpt-oss:20b)
• --host (default: http://localhost:11434)
• --db (default: ./.ollama_client/cache.sqlite)
• --keep-alive (default: 10m)
• --calls-per-minute (rate limit; 0 = off)
• --opt key=value (repeatable), --opts-json <JSON_OR_PATH>

Commands

# Ingest files (chunk + embed + store)
cloom ingest docs/**/*.md --strategy auto --opt num_ctx=16384

# Search similar chunks
cloom search "overshoot < 5%" --top-k 6

# Build a stitched context block
cloom context "controller step response" --top-k 6 --out ctx.md

# Single-shot generation (stream or non-stream)
cloom generate --prompt-file prompt.txt --opt temperature=0.2 --stream

# Chat (create/send/history)
cloom chat new --system "Be terse." --message "Hello"
cloom chat send --convo-id <UUID> --message "Add fuzz strategies" --stream
cloom chat history --convo-id <UUID>

# JSON mode (with or without Pydantic schema)
cloom json --prompt 'Return ONLY a JSON object with fields a, b'
cloom json --prompt-file spec.txt --schema mypkg.schemas:TestPlan

---

Recipes

1) Factual summary / plans (low hallucination)

cloom generate --prompt-file plan.txt \
  --opt temperature=0.1 --opt top_p=0.9 --opt repeat_penalty=1.1

2) Creative brainstorming

cloom generate --prompt "Invent 5 patch ideas." \
  --opt temperature=0.8 --opt top_p=0.95 --opt top_k=100

3) Structured JSON output

cloom json --prompt-file reqs.txt --schema mypkg.schemas:TestPlan \
  --opt temperature=0.0

4) Long-context retrieval + generation

cloom context "overshoot < 5%" --top-k 8 | \
  cloom generate --prompt "Using the following context, propose validation steps:"

5) Fast answers / debugging

cloom generate --prompt "Summarize 3 risks for communication transport." \
  --opt num_predict=200 --opt temperature=0.2

---

Templating

Register, list, and render prompt templates:

cloom template add --name plan --file templates/plan.md
cloom template list
cloom template render --name plan --var requirement=Use-Case-045 --var phase=init

Python:

client.register_template("risk", "List risks for {system} in {phase}.")
prompt = client.render_template("risk", system="communication transport", phase="init")
res = client.generate(prompt)

---

Streaming

Both generate and chat support streaming:

for tok in client.generate("Write a limerick:", stream=True):
    print(tok, end="", flush=True)

cid = client.new_conversation(system="Be concise.")
for delta in client.chat(cid, "Hello!", stream=True):
    print(delta, end="", flush=True)

---

Performance & scaling tips

• Keep the model warm: keep_alive="10m" avoids repeated loads for large models.
• Chunk sizing: default ~800 tokens with ~120 overlap balances coherence and precision.
• Context budget: prompt + context + response share num_ctx; cap num_predict if you pass long contexts.
• Determinism: set temperature=0.0 + seed for reproducible, auditable runs (especially JSON mode).
• Embedding cache: identical text reuses vectors; even after replace, cache avoids re-embedding.

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Tests, coverage, and CI

• Tests are written with the Goal to achieve 100% branch coverage (a practical proxy for MC/DC). Currently 97%
• GitHub Actions workflow runs:
  • Lint (ruff), type check (mypy)
  • pytest --cov=corpusloom --cov-branch --cov-fail-under=100
  • Uploads HTML coverage as an artifact

Run locally:

pytest -q --cov=corpusloom --cov-branch --cov-fail-under=100

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Troubleshooting

• Connection refused → Ensure ollama serve is running and the model is pulled.
• Model option ignored → Some options are model-dependent; verify your model supports it.
• Long prompts get cut → Increase num_ctx and/or reduce num_predict.
• JSON mode fails validation → The client retries with a repair prompt. If it still fails, reduce temperature and consider adding format="json".

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FAQ

Q: Where is data stored?
A: SQLite DB at --db (default ./.ollama_client/cache.sqlite) holds templates, messages, documents, chunks, and vectors (as JSON).

Q: Which embedding model is used?
A: Default is nomic-embed-text. Override via embed_model= in API calls or CLI flags.

Q: Can I swap the retriever?
A: Yes. The built-in retriever is cosine over stored vectors; you can replace it with FAISS/ANN later without changing high-level APIs.

Q: Do you support server-side JSON output?
A: You can set options={"format": "json"}. The Pydantic path is still recommended for robust validation.

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CorpusLoom — Local RAG + typed JSON on Ollama, wrapped in a clean Python API and cloom CLI.

Created on personal time and equipment; unrelated to Employer’s business.