envoyproxy/envoy

Tooling

tools/ holds the auxiliary scripts and binaries that orchestrate the project: code format, dependency management, API tooling, release scripts, and developer convenience commands. Most are Python; a few are Bash.

Format and lint

Path	Purpose
`tools/code_format/check_format.py`	The repo-wide formatter and linter. Has `check` and `fix` modes. Runs `clang-format`, header ordering, banned-token checks, license-header checks, BUILD-file ordering.
`tools/clang-format/`	Wrappers and config for `clang-format`.
`tools/clang-tidy/`	`clang-tidy` integration with the build.
`tools/spelling/`	Curated dictionary of project-specific terms used by the spell-check pre-commit.
`tools/local_fix_format.sh`	Format the files changed since `main` — the fast wrapper devs actually use.
`tools/path_fix.sh`	Fix `#include` paths after moving files.

API and proto tooling

The xDS API is large enough to need its own tooling.

Path	Purpose
`tools/api/`	API maintenance helpers (rename fields, version bumps).
`tools/api_proto_plugin/`	Shared library for protoc plugins that walk the API tree.
`tools/api_proto_breaking_change_detector/`	Diff old vs new protos to flag wire-format breaking changes. Runs in CI on every API change.
`tools/api_versioning/`	Bump API versions, manage `vNalpha`.
`tools/proto_format/`	Canonical `.proto` formatter.
`tools/protoprint/`	Proto descriptor → text. Used by the format tool.
`tools/protojsonschema/`	Generate JSON schemas from protos for editor integration.
`tools/protoshared/`	Shared helpers for the proto plugins.
`tools/type_whisperer/`	Track which types are used where in the API tree for impact analysis.

Dependency management

Path	Purpose
`tools/dependency/`	Validate, list, and update Bazel-fetched dependencies. Backs the `bazel/repositories.bzl` definitions.
`tools/check_repositories.sh`	CI gate for repo-pin updates.
`tools/update_crates.sh`	Refresh the `Cargo.lock` for Rust dependencies of the dynamic-modules ABI.
`tools/extensions/`	Maintain `extensions_metadata.yaml` in lockstep with `extensions_build_config.bzl`.
`tools/deprecate_features/`	Walk through deprecation lifecycle: warn → fatal → remove.
`tools/deprecate_guards/`	Helpers for runtime deprecation guards.

Release tooling

Path	Purpose
`tools/distribution/`	Distribution package descriptors for the Apt/Dnf release.
`tools/tarball/`	Source tarball generation for releases.
`tools/sha/`	SHA pin verifier.
`tools/github/`	GitHub-aware helpers (release-cut PR templates, `write_current_source_version.py` for tarball builds).

CI helpers

Path	Purpose
`tools/ci/`	CI helper scripts referenced by `.azure-pipelines/`.
`tools/coverage/`	LLVM coverage collection and reporting.
`tools/docker_wrapper.sh`	Run a command inside the official Envoy build image.
`tools/bazel-test-docker.sh`	Run a Bazel test inside the build image.

Developer environment

Path	Purpose
`tools/vscode/`	VS Code launch + IntelliSense configuration.
`tools/dev/`	Random developer convenience commands.
`tools/debugging/`	Debugging helpers.
`tools/find_related_envoy_files.py`	Given `source/foo.cc`, find the matching header, test, and mock.
`tools/gen_compilation_database.py`	Produce `compile_commands.json` for clangd.
`tools/stack_decode.py`	Symbolicate Envoy crash backtraces.
`tools/build_profile.py`	Visualise where Bazel build time is going.
`tools/envoy_collect/`	Collect Envoy logs/admin output for diagnostic bundles.
`tools/h3_request/`	Minimal HTTP/3 client used to manually exercise QUIC paths.
`tools/socket_passing/`	Helpers for hot restart socket-passing tests.

Bootstrap conversion

tools/bootstrap2pb/ and tools/bootstrap2pb.cc — convert a YAML bootstrap into the binary protobuf representation, useful for embedded environments where YAML parsing isn't desirable.

Pre-commit and Git hooks

The project ships pre-commit hooks under support/; see support/README.md. The hooks automate format checking, DCO sign-off, license-header checks, and the spelling pass before git push.

Repokitteh

Not strictly under tools/, but worth noting: repokitteh.star at the repo root is a Starlark configuration for the repokitteh GitHub bot, which handles slash-command-driven CI re-runs, automatic reviewer assignment from reviewers.yaml, and merge-on-green workflows. If a PR comment is structured like /retest or /lgtm, repokitteh is what acts on it.