diffctx — what a git change reaches, and the code to review it

diffctx tells an agent or a reviewer what a change reaches outside its diff — the callers, the tests that reach them, the contracts it crosses — and selects the code needed to understand it under a token budget. Local, deterministic, no index, no model calls. Caller resolution is static and per language; where it cannot resolve, the answer says so instead of printing a zero.

Formerly published as treemapper — every command, flag, and API call works unchanged.

Install

# Claude Code: the MCP server, /diffctx:impact, and hooks that run it on each commit and push
claude plugin marketplace add nikolay-e/diffctx
claude plugin install diffctx@diffctx

# any MCP client
claude mcp add diffctx -- uvx --from 'diffctx[mcp]' diffctx-mcp

# CLI, zero-install
uvx diffctx . --diff HEAD~1

pipx, pip, cargo, npm, Docker, Scoop, other MCP clients and the Python API: integrations.

Usage

diffctx . --diff --mode impact          # uncommitted work: callers outside the diff, their tests, contracts
diffctx . --symbol parse_config         # the same for a name, no change needed
diffctx . --diff main...feature         # the code to review a branch, packed under the auto budget
diffctx . --diff HEAD~1 --budget 12000  # the last commit, capped at 12k o200k tokens
diffctx . --diff 24h --mode locate      # today's work as ranked JSON, no source bodies
diffctx .                               # whole-tree export, Markdown

--diff takes a git range, staged, or a duration window ending now (24h, 90min, 2w). Every flag, default and exit code: command-line reference.

diffctx demo

How it compares

Whole-repo packers export everything; code-graph servers answer queries against a maintained index. diffctx is diff-seeded: the input is a change, the output is what it touches and what explains it. Measured results, and when the other two fit better: COMPARISON.md.

Documentation site — the pipeline end to end
Command-line reference — rendered from diffctx --help
Integrations — install, MCP clients, Python API
FAQ — heuristic or oracle, ignore rules, monorepos, secrets
Token counting — --budget for non-GPT models
GitHub Action — diff context as a CI step
Benchmarks and the paper
Changelog · Security
Parameter strategy

Apache 2.0

Metadata

Release files for diffctx 1.19.1

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for diffctx 1.19.1
File	Size	Uploaded
diffctx-1.19.1.tar.gz	674.6 kB	Oct 14, 2026	Details

Built distributions (wheels)

Table of built distributions (wheels) for diffctx 1.19.1
File	Interpreter	ABI	Platform	Reset
diffctx-1.19.1-cp314-cp314t-win_arm64.whl 10.5 MB Oct 14, 2026	CPython 3.14	CPython 3.14 free-threading	Windows ARM64	Details
diffctx-1.19.1-cp314-cp314t-win_amd64.whl 10.9 MB Oct 14, 2026	CPython 3.14	CPython 3.14 free-threading	Windows x86-64	Details
diffctx-1.19.1-cp314-cp314t-manylinux_2_28_x86_64.whl 10.8 MB Oct 14, 2026	CPython 3.14	CPython 3.14 free-threading	Linux glibc 2.28+ x86-64	Details
diffctx-1.19.1-cp314-cp314t-manylinux_2_28_aarch64.whl 10.5 MB Oct 14, 2026	CPython 3.14	CPython 3.14 free-threading	Linux glibc 2.28+ ARM64	Details
diffctx-1.19.1-cp314-cp314t-macosx_11_0_arm64.whl 10.8 MB Oct 14, 2026	CPython 3.14	CPython 3.14 free-threading	macOS 11.0+ ARM64	Details
diffctx-1.19.1-cp314-cp314t-macosx_10_12_x86_64.whl 10.7 MB Oct 14, 2026	CPython 3.14	CPython 3.14 free-threading	macOS 10.12+ x86-64	Details
diffctx-1.19.1-cp310-abi3-win_arm64.whl 10.5 MB Oct 14, 2026	CPython 3.10	abi3	Windows ARM64	Details
diffctx-1.19.1-cp310-abi3-win_amd64.whl 10.9 MB Oct 14, 2026	CPython 3.10	abi3	Windows x86-64	Details
diffctx-1.19.1-cp310-abi3-manylinux_2_28_x86_64.whl 10.8 MB Oct 14, 2026	CPython 3.10	abi3	Linux glibc 2.28+ x86-64	Details
diffctx-1.19.1-cp310-abi3-manylinux_2_28_aarch64.whl 10.5 MB Oct 14, 2026	CPython 3.10	abi3	Linux glibc 2.28+ ARM64	Details
diffctx-1.19.1-cp310-abi3-macosx_11_0_arm64.whl 10.8 MB Oct 14, 2026	CPython 3.10	abi3	macOS 11.0+ ARM64	Details
diffctx-1.19.1-cp310-abi3-macosx_10_12_x86_64.whl 10.7 MB Oct 14, 2026	CPython 3.10	abi3	macOS 10.12+ x86-64	Details

Total release size: 129.2 MB

Release files / diffctx-1.19.1.tar.gz

Download URL	diffctx-1.19.1.tar.gz
Size	674.6 kB
Tags	Source
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1.tar.gz
SHA-256 checksum: 025aae2efe356a5f5f902d2987edd61c930676102b47be5bd77460b68cf59ef3 Verifying attestations

Release files / diffctx-1.19.1-cp314-cp314t-win_arm64.whl

Download URL	diffctx-1.19.1-cp314-cp314t-win_arm64.whl
Size	10.5 MB
Tags	CPython 3.14 CPython 3.14 free-threading Windows ARM64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

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Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp314-cp314t-win_arm64.whl
SHA-256 checksum: 747436060e67fc86c7577233bcc3c193b38bb21e287c2e11141c037399761903 Verifying attestations

Release files / diffctx-1.19.1-cp314-cp314t-win_amd64.whl

Download URL	diffctx-1.19.1-cp314-cp314t-win_amd64.whl
Size	10.9 MB
Tags	CPython 3.14 CPython 3.14 free-threading Windows x86-64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp314-cp314t-win_amd64.whl
SHA-256 checksum: 28b8f6c85d5b392bc99dc6bbc9816cd22d5976de58e79c8a6f1356786d207e93 Verifying attestations

Release files / diffctx-1.19.1-cp314-cp314t-manylinux_2_28_x86_64.whl

Download URL	diffctx-1.19.1-cp314-cp314t-manylinux_2_28_x86_64.whl
Size	10.8 MB
Tags	CPython 3.14 CPython 3.14 free-threading Linux glibc 2.28+ x86-64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp314-cp314t-manylinux_2_28_x86_64.whl
SHA-256 checksum: 33c5a2865849dc07fba98dc004e996b9127cc8cefa167d66b3c769cf32adc5a8 Verifying attestations

Release files / diffctx-1.19.1-cp314-cp314t-manylinux_2_28_aarch64.whl

Download URL	diffctx-1.19.1-cp314-cp314t-manylinux_2_28_aarch64.whl
Size	10.5 MB
Tags	CPython 3.14 CPython 3.14 free-threading Linux glibc 2.28+ ARM64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

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Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp314-cp314t-manylinux_2_28_aarch64.whl
SHA-256 checksum: 49426a6ba719d7caf9cbdf3393e093a406ba91ebe47f2e36aa2484d70b0d3043 Verifying attestations

Release files / diffctx-1.19.1-cp314-cp314t-macosx_11_0_arm64.whl

Download URL	diffctx-1.19.1-cp314-cp314t-macosx_11_0_arm64.whl
Size	10.8 MB
Tags	CPython 3.14 CPython 3.14 free-threading macOS 11.0+ ARM64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp314-cp314t-macosx_11_0_arm64.whl
SHA-256 checksum: 4ae494fa8b7d62be7ff902086384afc6700b01317177404fef29d78849d9af54 Verifying attestations

Release files / diffctx-1.19.1-cp314-cp314t-macosx_10_12_x86_64.whl

Download URL	diffctx-1.19.1-cp314-cp314t-macosx_10_12_x86_64.whl
Size	10.7 MB
Tags	CPython 3.14 CPython 3.14 free-threading macOS 10.12+ x86-64
SHA-256 checksum How to use checksums	`766e83405ff3738377c0cf37eb6436d6fe90e8fed5eef5cd85d004dbe30a88e8`
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp314-cp314t-macosx_10_12_x86_64.whl
SHA-256 checksum: 766e83405ff3738377c0cf37eb6436d6fe90e8fed5eef5cd85d004dbe30a88e8 Verifying attestations

Release files / diffctx-1.19.1-cp310-abi3-win_arm64.whl

Download URL	diffctx-1.19.1-cp310-abi3-win_arm64.whl
Size	10.5 MB
Tags	CPython 3.10 Windows ARM64 abi3
SHA-256 checksum How to use checksums	`4ec2fd797f8c39da9e001a92c2bd4fd7ca1e902ddffd2c2849650f8ec3c70fd5`
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp310-abi3-win_arm64.whl
SHA-256 checksum: 4ec2fd797f8c39da9e001a92c2bd4fd7ca1e902ddffd2c2849650f8ec3c70fd5 Verifying attestations

Release files / diffctx-1.19.1-cp310-abi3-win_amd64.whl

Download URL	diffctx-1.19.1-cp310-abi3-win_amd64.whl
Size	10.9 MB
Tags	CPython 3.10 Windows x86-64 abi3
SHA-256 checksum How to use checksums	`24aa72eb5e4a6333ca278a32f95daa16a8a18bc16875365faea69c6130f8dc7e`
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp310-abi3-win_amd64.whl
SHA-256 checksum: 24aa72eb5e4a6333ca278a32f95daa16a8a18bc16875365faea69c6130f8dc7e Verifying attestations

Release files / diffctx-1.19.1-cp310-abi3-manylinux_2_28_x86_64.whl

Download URL	diffctx-1.19.1-cp310-abi3-manylinux_2_28_x86_64.whl
Size	10.8 MB
Tags	CPython 3.10 Linux glibc 2.28+ x86-64 abi3
SHA-256 checksum How to use checksums	`87abe0923961fec1dd34a27ab42975e443f70eaa686c905ddf95aecec8de9221`
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp310-abi3-manylinux_2_28_x86_64.whl
SHA-256 checksum: 87abe0923961fec1dd34a27ab42975e443f70eaa686c905ddf95aecec8de9221 Verifying attestations

Release files / diffctx-1.19.1-cp310-abi3-manylinux_2_28_aarch64.whl

Download URL	diffctx-1.19.1-cp310-abi3-manylinux_2_28_aarch64.whl
Size	10.5 MB
Tags	CPython 3.10 Linux glibc 2.28+ ARM64 abi3
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

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Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp310-abi3-manylinux_2_28_aarch64.whl
SHA-256 checksum: d2b09b0017a6649b97d36c2241e2eb8211c901653cdff5806b02a0f96a476e0f Verifying attestations

Release files / diffctx-1.19.1-cp310-abi3-macosx_11_0_arm64.whl

Download URL	diffctx-1.19.1-cp310-abi3-macosx_11_0_arm64.whl
Size	10.8 MB
Tags	CPython 3.10 abi3 macOS 11.0+ ARM64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp310-abi3-macosx_11_0_arm64.whl
SHA-256 checksum: 8ae913710ed70187d3c53ea057d98845bf781c855e4af11f1ad6e1f2acc47c9b Verifying attestations

Release files / diffctx-1.19.1-cp310-abi3-macosx_10_12_x86_64.whl

Download URL	diffctx-1.19.1-cp310-abi3-macosx_10_12_x86_64.whl
Size	10.7 MB
Tags	CPython 3.10 abi3 macOS 10.12+ x86-64
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Upload date	Oct 14, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/nikolay-e/diffctx
Publishing commit: github.com/nikolay-e/diffctx/tree/37e0b09568ea24d3403b8b766e76d2aadc4a608a

Workflow

Publishing configuration: github.com/nikolay-e/diffctx/blob/37e0b09568ea24d3403b8b766e76d2aadc4a608a/.github/workflows/cd.yml
Publishing logs: github.com/nikolay-e/diffctx/actions/runs/38618336151/attempts/1

Artifact

Subject: diffctx-1.19.1-cp310-abi3-macosx_10_12_x86_64.whl
SHA-256 checksum: d40465ba7c11038cd97e3019a5c02b350683f4c654a0f5fc89ed477c08d85bb7 Verifying attestations