petromcp

petromcp

Read well logs with Claude without the data ever leaving your machine.

petromcp is an MCP server for petroleum data formats, built for teams whose files legally cannot be uploaded to a cloud service. No telemetry, no phone-home, no automatic updates, and a default-deny path allowlist that refuses to open anything you have not explicitly permitted. LAS today; DLIS, SEG-Y, and pump cards next.

If you can upload your data somewhere, you have more options than this. If you can't, this was written for you.

What this gives you

LLM hosts cannot read binary or semi-structured petroleum formats. petromcp wraps the established open-source parsers — lasio and dlisio today, with segyio queued for a later slice — and exposes them as MCP tools, so you can have a conversation with your data instead of copy-pasting curve values into chat.

What "local-first" means here, concretely

Not a posture. Four things you can verify in the source:

• Default deny. A fresh install can read nothing. Access is granted per directory, and every tool routes through one validator that resolves symlinks before checking, so a link inside an allowed directory cannot reach outside it. There is no environment variable that widens the allowlist and no tool that changes it at runtime.
• No network, declared. petromcp opens no outbound connections. All five tools ship openWorldHint: false and readOnlyHint: true, so your host can verify that claim rather than take it.
• An audit trail. Every tool call is logged with a timestamp, the tool name, and the resolved path.
• Bounded output. Curve reads are capped and report downsampled and original_count, so a 20,000-point log cannot silently dump into a context window.

The threat model, and what does not count as a vulnerability, are in SECURITY.md. Read docs/DATA_PRIVACY.md before pointing this at real data — it is authoritative, and if the code contradicts it the code is the bug.

Install

Requires Python 3.10+ and uv.

Add petromcp to your MCP host's config — no clone, no build:

{
  "mcpServers": {
    "petromcp": {
      "command": "uvx",
      "args": ["petroleum-mcp", "serve"]
    }
  }
}

On macOS that file is ~/Library/Application Support/Claude/claude_desktop_config.json. Restart the host afterwards. macOS notes and troubleshooting: docs/INSTALL.md.

To work on petromcp rather than just use it:

git clone https://github.com/ameyxd/petromcp
cd petromcp
make setup
make install-claude

Configure

By default petromcp can read nothing. Tell it which directories are fair game:

uvx petroleum-mcp config init
uvx petroleum-mcp config add-path ~/petroleum/wells

Or, if you want to try it without your own data, generate the synthetic sample from a checkout and allowlist that:

make generate
uvx petroleum-mcp config add-path "$(pwd)/examples/sample_data"

Restart your MCP host after editing the allowlist — it is read once at startup.

Use

Open a new conversation and ask, in plain language:

What's wrong with this well log? /path/to/well.las
Compare these two wells: /path/to/A.las and /path/to/B.las
Convert 1500 psi to kPa.

Claude picks the right tool, reads the file through petromcp, and answers.

Worked examples, with real tool output rather than prose:

• QC a well log — finds a planted density gap, a washout, and a gamma ray spike
• Compare two wells — depth overlap, a missing curve, and a unit mismatch that is invisible in one file
• Unit conversion
• Read a DLIS file — logical files, frames, and what happens when a channel name is ambiguous

Every value in those documents is generated by calling the tools; CI fails if they drift.

Tools

Tool	What it does
read_las_file	Header-level summary of a LAS file
summarize_las_curves	Per-curve min, max, mean, stddev, gap percentage
read_las_curve	Depths and values for one curve, with sampling cap
compare_well_logs	Common curves, depth overlap, unit consistency, flags
convert_units	ft<->m, psi<->kPa, psi<->bar, bbl<->m3, degF<->degC, mD<->m2
list_supported_units	Every convertible pair with its physical quantity
read_dlis_file	DLIS structure: logical files, frames, index types
list_dlis_channels	Every DLIS channel with its frame, units, and length
read_dlis_channel	One DLIS channel's values, with a sampling cap
qc_a_well_log prompt	Walks Claude through a standard QC pass

Every tool is read-only and opens no network connection, and declares that in its MCP annotations. Full reference: docs/TOOLS_REFERENCE.md.

DLIS files hold several logging runs, each with several frames, so a channel name is unique only within a frame. read_dlis_channel refuses an ambiguous name and lists the candidates rather than guessing, because the values differ.

SEG-Y and pump card support land in subsequent releases.

Status

v0.7 ships the LAS and DLIS slices, a comparison tool, a units utility, and config-management CLI subcommands. The remaining formats are tracked in SPEC_petromcp.md. The non-goals list there is real; read it before filing feature requests.

Release history: CHANGELOG.md. Security policy and threat model: SECURITY.md.

License

MIT.

mcp-name: io.github.ameyxd/petromcp

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Built by Amey Ambade. I write about AI systems in industries where the data can't leave the building, at writing.heyamey.com.