OmniFetcher

One typed shape for every data source.

Jira, Postgres, PDFs, S3, Slack, Kafka, GitHub, Confluence — 30 sources, one contract. The code that reads one reads them all. Ships an MCP server, so your LLM agents can fetch from any of them through a single tool.

pip install omni-fetcher

The problem, in one screen

Pulling from four sources today means four SDKs, four auth models, four response shapes, and four ways to fail:

# GitHub — PyGithub
issue = Github(token).get_repo("psf/requests").get_issue(42)
text  = issue.body                                    # comments? separate call, separate shape

# Jira — atlassian-python-api
data  = Jira(url, username=u, password=t).issue("PROJ-1")
text  = data["fields"]["description"]                 # dict-diving, and it raises on 404

# A PDF — pypdf
text  = "\n".join(p.extract_text() for p in PdfReader("report.pdf").pages)

# Postgres — asyncpg
rows  = await (await asyncpg.connect(dsn)).fetch("SELECT id, email FROM users LIMIT 10")
text  = ...                                           # rows aren't text. and read-only? that's on you.

Now write the error handling. Four times. Now add a fifth source.

With OmniFetcher, it's one loop:

from omni_fetcher.v1 import AtomKind, OmniFetcher, Success, builtin_registry

omni = OmniFetcher(builtin_registry())

for uri in [
    "https://github.com/psf/requests/issues/42",
    "jira://issue/PROJ-1",
    "report.pdf",
    "postgres://db.internal/app?query=SELECT%20id,email%20FROM%20users%20LIMIT%2010",
]:
    result = await omni.fetch(uri, auth=creds_for(uri))   # your credential lookup
    if isinstance(result, Success):                       # -> one typed Result, every source
        text = "\n".join(a.content for a in result.tree.find_atoms(AtomKind.TEXT))
        print(uri, "→", len(text), "chars")

Same call. Same result type. Same three moves every time: check the state, walk the tree, read the atoms. No if source == "jira". Ever.

Who it's for

• Building RAG or agent context — you need many heterogeneous sources in one shape, with provenance and honest failures, not thirty bespoke parsers.
• Internal tools and glue services — one dependency instead of a dozen SDKs, and one error model instead of a dozen exception hierarchies.
• Anyone wiring an LLM to real data — the MCP server does it with no glue code at all.

For agents: one MCP server, every source

pip install "omni-fetcher[mcp]"

omni-fetcher-mcp is a stdio MCP server that hands a model three tools:

Credentials are host-configured (OMNI_FETCHER_GITHUB_TOKEN, OMNI_FETCHER_POSTGRES_PASSWORD, …) and injected per call — a token never enters the model's context. Point Claude Desktop, Claude Code, or any MCP client at it and the model pulls a Jira ticket, a database row, and a PDF into context through one interface.

Two agent skills ship too: one teaches an agent the contract, one assembles context from a set of sources.

How it compares

Honest positioning — these tools are good at what they do; they solve a differently-shaped problem:

Why it's built this way

The connectors are interchangeable plumbing. The typed shape they emit is the point — and these are the bets behind it, all tested:

• Errors are values, not exceptions. A missing resource, a bad credential, a parse failure comes back as a typed Error(kind) you branch on — not a try/except you forgot to write. Partial data comes back as Partial with typed gaps naming exactly what's missing, so you never silently lose the half that worked.
• Stateless, multi-tenant by construction. Connectors hold no credentials and no data between calls; you pass auth per call. One shared orchestrator serves every tenant concurrently — proven by a test that drives it from 16 threads and 64 interleaved coroutines and asserts zero cross-tenant leakage.
• Read-only means read-only — enforced by the engine, not a regex. The SQL connectors run every query inside a READ ONLY transaction (Postgres/MySQL) or a mode=ro open (SQLite). A write is refused by the database, not by us trying to parse your SQL. Verified against real Postgres, MySQL, and MariaDB.
• Zoom is semantic, not token-chopping. Ask for text at paragraph or sentence depth and you get the source's own structure, split losslessly — never an arbitrary character window. Ask for a depth a source can't provide and you get an honest gap, not a silent no-op.

The full rationale — including what OmniFetcher deliberately refuses to be — is in PHILOSOPHY.md.

The contract

Every fetch returns a Result. That's the whole surface you branch on:

Result
├── Success ── tree: CompositionNode
├── Partial ── tree + gaps: list[Gap]        # what came back, plus typed holes
└── Error ──── kind: ErrorKind + message     # returned as a value, never raised

CompositionNode          # exactly two fields — no surprises
├── metadata: Metadata   # id, kind, tags, created, updated, author, source_url
│                        #   + source_extra["<source>"] for the source-only fields
└── children: [ ... ]    # a MIXED list, in document order:
                         #   CompositionNode | Text | Image | Audio | Video | Table

Content and metadata are separate on purpose: fields every source has (id, author, timestamps, source_url) are typed on Metadata; anything only one source has is namespaced under source_extra["jira"], so it can't collide with your generic code and can't leak into it.

30 sources — and counting

Don't trust a list in a README — ask the installed package what it can actually reach (only sources whose extras are installed show up):

omni-fetcher v1 sources          # a table of every routable source + bounded/stream flag
omni-fetcher v1 sources --json   # the same, as JSON

60 seconds

import asyncio
from omni_fetcher.v1 import AtomKind, Success
from omni_fetcher.v1.connectors.local_file import LocalFileFetcher

async def main() -> None:
    result = await LocalFileFetcher().fetch("README.md")
    if isinstance(result, Success):
        for atom in result.tree.find_atoms(AtomKind.TEXT):
            print(atom.content[:100])

asyncio.run(main())

Optional extras gate a source or capability: office, jira, confluence, elasticsearch, kafka, websockets, postgres, mysql, gdrive, web, mcp. Everything else works on the core install.

A few more moves

Handle all three states — expected failures are values:

result = await connector.fetch(uri)
if isinstance(result, Success):
    ...                       # result.tree
elif isinstance(result, Partial):
    ...                       # result.tree + result.gaps  (don't throw this away)
elif isinstance(result, Error):
    ...                       # result.kind, result.message

Auth per call — nothing is stored, which is what makes it multi-tenant-safe:

await JiraConnector().fetch("jira://issue/PROJ-1",
                            auth=BasicAuth(username="dev@acme.io", password="api-token"))
await SlackConnector().fetch("slack://channel/C0123456789",
                             auth=BearerAuth(token="xoxb-..."))

Consume a stream — resumable across drops:

async for item in omni.stream("tail:///var/log/app.log?from=end"):
    if isinstance(item, Success):
        print(item.tree.find_atoms(AtomKind.TEXT)[0].content)

Or skip Python — the CLI takes credentials as env-var names, so no secret touches argv:

omni-fetcher v1 fetch "sqlite:///app.db?query=SELECT%20*%20FROM%20users" --json
omni-fetcher v1 fetch "jira://issue/PROJ-1" \
  --auth-type basic --username-env JIRA_USER --password-env JIRA_TOKEN
omni-fetcher v1 stream "kafka://localhost:9092/events?offset=earliest" --json --max-items 100

Write a connector — subclass BaseFetcher, override stream(), and fetch() comes free. Any built-in's exact URI/auth/options live in its module docstring (python -c "from omni_fetcher.v1.connectors import mysql; print(mysql.__doc__)"), which never drifts from the code.

Status

v1.10, MIT, ~1,300 tests, Python 3.10–3.12. The v1 contract is stable and additive — new connectors slot in without changing the shape you code against. Issues and connector contributions welcome; if a source you need is missing, the custom-connector path above is about twenty lines.

Development

git clone https://github.com/Jainil-Gosalia/omni_fetcher
cd omni_fetcher
pip install -e ".[dev,office,web,gdrive,confluence,slack,jira,kafka,mcp,mysql]"

pytest --ignore=tests/integration     # unit + contract suites
ruff check . && ruff format --check . && mypy omni_fetcher/

CI runs the same gates on Python 3.10–3.12. Releases are tag-driven: a GitHub Release vX.Y.Z builds, gates, and publishes to PyPI via trusted publishing. The pre-1.0 API still ships unchanged; docs/migration-v1.md maps it onto the contract above.

License

MIT © 2024–2026 OmniFetcher Contributors