sharkdp/fd

Can another program use it through a documented, machine-readable surface?

• next: L3 Machine-readable output (--json/--format) and documented exit statuses. (no --json/--format option)

cli ladder · level 2

• ✓ L1 Invocable non-interactively: no prompts, or prompts guarded by a TTY check or a --yes/--no-input option. no interactive prompts
• ✓ L2 --help documents every option (at least 90% of options have help text). src/cli.rs 6 matches
• ✗ L3 Machine-readable output (--json/--format) and documented exit statuses. no --json/--format option
• ✗ L4 The output format is specified by a JSON Schema. no JSON Schema for the output

Can integrators rely on it not changing under them?

• next: L3 A deprecation mechanism is used in code (warnings, @deprecated, Deprecation/Sunset headers) or the API is versioned. (no deprecation mechanism or API versioning)

all ladder · level 2

• ✓ L1 Releases are versioned (semver tags or versioned changelog sections). 45 semver tags, latest v10.5.0
• ✓ L2 A changelog exists and marks breaking changes. CHANGELOG.md marks breaking changes
• ✗ L3 A deprecation mechanism is used in code (warnings, @deprecated, Deprecation/Sunset headers) or the API is versioned. no deprecation mechanism or API versioning
• ✓ L4 Across tagged releases, no OpenAPI operation, CLI option or __all__ symbol was removed without first being deprecated. 20 tagged releases compared

Can others react to state changes without polling?

Can a machine act with its own revocable, least-privilege identity?

Can its data get in and out, in bulk, in open formats, with an explicit schema?

Can an automated caller use it without guessing, and recover from failure?

• next: L3 Documented exit statuses distinguish error classes, errors are JSON in JSON mode, and color is off when not a TTY. (errors aren't JSON in JSON mode)

cli ladder · level 2

• ✓ L1 Never blocks on a prompt when stdin is not a TTY. no interactive prompts
• ✓ L2 Data on stdout, diagnostics on stderr, non-zero exit on failure. src/error.rs 1 matchsrc/main.rs 1 match
• ✗ L3 Documented exit statuses distinguish error classes, errors are JSON in JSON mode, and color is off when not a TTY. errors aren't JSON in JSON mode
• ✗ L4 --dry-run, limits for long or costly operations (timeouts, budgets), and agent docs. no --dry-run

Can another system run and compose it without a human?

• next: L3 Published to a public registry and run non-interactively in CI. (not published to a registry)

cli ladder · level 2

• ✓ L1 Runnable from source (a declared entry point). Cargo.toml cargo binsrc/main.rs cargo binary
• ✓ L2 Installable as a package that provides the command. Cargo.toml cargo binsrc/main.rs cargo binary
• ✗ L3 Published to a public registry and run non-interactively in CI. not published to a registry
• ✗ L4 Also shipped as a container image or a single binary. no container image or binary

Can behaviour be added without modifying the code?

• next: L1 Internal seams: a registry, registration function or plugin manager. (no registry or registration function)

all ladder · level 0

• ✗ L1 Internal seams: a registry, registration function or plugin manager. no registry or registration function
• ✗ L2 The docs show how to add behaviour through those seams (even in-tree). no registration functions to document
• ✗ L3 Out-of-tree extensions are discovered (entry points, a plugin directory, configuration) without editing the package. extensions must be added inside the package
• ✗ L4 The extension API is versioned, has lifecycle hooks, and has example extensions. the extension API isn't versioned

Can an operator, or an orchestrating agent, tell whether it works and why not?

• next: L2 Verbosity control for diagnostics (--quiet, --log-level, --debug). (no --quiet or log-level control)

cli ladder · level 1

• ✓ L1 Meaningful exit statuses, and errors on stderr. src/error.rs 1 matchsrc/main.rs 1 match
• ✗ L2 Verbosity control for diagnostics (--quiet, --log-level, --debug). no --quiet or log-level control
• ✗ L3 Structured logs (e.g. --log-format json) or a machine-readable run summary. no structured diagnostics
• ✗ L4 Tracing hooks (OpenTelemetry). no tracing hooks

Can an agent change it safely with limited context?

• next: L4 No import cycles, and agent docs (AGENTS.md, CLAUDE.md, llms.txt). (no agent docs (AGENTS.md, CLAUDE.md, llms.txt))

all ladder · level 3

• ✓ L1 A README and some tests. README.mdtests/testenv/mod.rs 2 test files
• ✓ L2 CI runs the tests; applications pin dependencies (libraries and zero-dependency projects are exempt). .github/workflows/CICD.ymlCargo.lock
• ✓ L3 At least 90% of modules fit 32k tokens and no file exceeds 12k; test/source token ratio at least 0.3; at least 70% of the code is typed. tests/testenv/mod.rs test ratio 0.51, 96% typed, modules fit
• ✗ L4 No import cycles, and agent docs (AGENTS.md, CLAUDE.md, llms.txt). no agent docs (AGENTS.md, CLAUDE.md, llms.txt)