bun

Incredibly fast JavaScript runtime, bundler, test runner, and package manager

65% pass rate

2/8 principles met

Spec Coverage

How many of the spec's requirements were verified for this tool. See /coverage for the full matrix.

Level	Total	Verified	Unverified
MUST	28	19	9
SHOULD	21	13	8
MAY	10	10	0

Top Issues

FAIL Rejects invalid arguments Fail-Fast, Actionable Errors binary silently accepted invalid flag (exit 0)
FAIL Structured-output CLI exposes its schema at runtime Structured, Parseable Output CLI emits structured output but exposes no `schema` subcommand or `--schema` flag at top level or nested one level deep. Agents need a runtime-discoverable schema to pin against shape changes.
FAIL Bad invocation exits with structured usage-error code (2) Structured, Parseable Output binary silently accepted invalid flag (exit 0). Bad invocation must signal usage error via a non-zero exit code.

All Audits

P1: Non-Interactive by Default

PASS	Non-interactive by default
SKIP	Non-interactive gate flag advertised in --help	target satisfies P1 via alternative gate (help-on-bare or stdin-primary)
PASS	Flags advertise env-var bindings in --help
PASS	Secret-bearing flags expose stdin or *-file companion
PASS	`--help` advertises default values for flags
WARN	Rich-TUI affordance for TTY contexts	no rich-TUI affordance detected (no `--tui`/`--interactive`/`--ui` flag, no spinner/progress/tui mention in --help). MAY-tier — rich TUI in TTY contexts is a nice-to-have, not required.

P2: Structured, Parseable Output

WARN	Structured output support	--output/--format flag detected but could not validate JSON via safe probes (--help/--version override output flags in most CLIs)
FAIL	Structured-output CLI exposes its schema at runtime	CLI emits structured output but exposes no `schema` subcommand or `--schema` flag at top level or nested one level deep. Agents need a runtime-discoverable schema to pin against shape changes.
WARN	--json / --jsonl short aliases for --output	no --json or --jsonl short alias found. Agents and pipelines benefit from short forms alongside the canonical `--output` enum.
WARN	`--raw` flag for pipe-safe unformatted output	no `--raw` flag advertised. MAY-tier — useful for pipelines that want to strip formatting before piping to other tools.
SKIP	`--output` advertises additional formats beyond text/json	no `--output` or `--format` flag advertised; vacuous skip for MAY-tier extra formats.
FAIL	Bad invocation exits with structured usage-error code (2)	binary silently accepted invalid flag (exit 0). Bad invocation must signal usage error via a non-zero exit code.
SKIP	Errors emit JSON envelope with `error`/`kind`/`message` under `--output json`	binary does not advertise `--output json` in --help; MUST applies only to CLIs that opt into the JSON contract.
SKIP	JSON success and error envelopes share their non-payload key set	binary does not advertise `--output json` in --help; envelope-consistency only applies to CLIs that opt into the JSON contract.

P3: Progressive Help Discovery

PASS	Help flag produces useful output
PASS	Version flag works (`--version` plus short alias)
PASS	Version flag works (`--version` plus short alias)
WARN	`examples` subcommand or `--examples` flag for curated usage patterns	no `examples` subcommand or `--examples` flag found. MAY-tier — a curated usage block keeps agents from hunting through long help text.
PASS	Short `-h` summary differs from `--help` long form
FAIL	Each subcommand's `--help` ships at least one invocation example	subcommands missing example invocations in their `--help`: lint. Examples teach agents the call shape faster than option tables; use clap's `after_help` or a dedicated `Examples:` block.
WARN	Help text pairs human and `--output json` example invocations	no paired text + `--output json` example found within 5 lines in top-level or any subcommand `--help`. Pairing keeps agents from reverse-engineering the JSON invocation from the text one.

P4: Fail-Fast, Actionable Errors

FAIL	Rejects invalid arguments	binary silently accepted invalid flag (exit 0)
FAIL	Error messages include a hint or remediation phrase	stderr was empty on bad invocation. Argument parsers must explain why the input was rejected — silent failure forces the agent to guess.
SKIP	`--output json` produces JSON-formatted errors	binary does not advertise `--output json` in --help; SHOULD applies only to CLIs that opt into the JSON contract.

P5: Safe Retries & Mutation Boundaries

SKIP	Destructive subcommands require `--force` or `--yes`	no destructive subcommands detected; MUST applies conditionally to CLIs with destructive operations.
SKIP	Read and write surfaces are both visible in subcommand list	no recognizable read or write subcommand verbs; the read/write distinction is unobservable from the help surface alone.

P6: Composable, Predictable Command Structure

PASS	Handles SIGPIPE gracefully
WARN	Pager-using CLI ships --no-pager escape hatch	pager referenced in --help but no --no-pager escape hatch advertised
PASS	Respects NO_COLOR
WARN	Subcommand verbs follow community-standard names	3/6 subcommand(s) follow standard verb names. Non-standard: lint, x, repl. MAY-tier — community-standard verbs (get/list/create/update/delete) help agents predict subcommand behavior across CLIs.
WARN	`--color` flag for explicit color control	no `--color` flag advertised. MAY-tier — `auto\|always\|never` lets agents and pipelines override the TTY-based default.
WARN	Input-accepting commands read from stdin when no file is given	input-accepting subcommand present but `--help` does not mention stdin or `-` as a path placeholder. SHOULD-tier — agents piping data into the tool expect stdin to work when no file arg is provided.
PASS	Subcommand naming follows a consistent verb/noun convention
WARN	Operations are subcommands, not verb-shaped flags	top-level verb-shaped flag(s) found: --install. Operations belong under the `Commands:` block (`tool search "q"`), not on the flag namespace where they fight the `--help` filtering agents rely on.

P7: Bounded, High-Signal Responses

WARN	Quiet mode available	no --quiet/-q flag detected in --help output
PASS	`--verbose` flag for diagnostic escalation
SKIP	`--limit` / `--max-results` flag for list operations	no list-style subcommand detected (list/ls/search/query/find/show/get); vacuous skip for the list-only SHOULD.
SKIP	Cursor-based pagination flags for list traversal	no list-style subcommand detected; vacuous skip for the list-only MAY.
WARN	`--timeout` flag for long-running operations	long-running subcommand present but no timeout flag advertised (looked for --timeout, --deadline, --max-time). SHOULD-tier — without a bound, agents that hit a hung operation have to enforce timeouts externally.
WARN	Help text advertises TTY-aware verbosity behavior	no TTY-aware language found in `--help`. MAY-tier — automatic verbosity reduction when stdout is piped or redirected lets agents skip the explicit `--quiet` flag. Behavioral probes cannot simulate a real TTY without a pty crate, so this audit relies on documented intent.

P8: Discoverable Through Agent Skill Bundles

PASS	Skill bundle has install path (`tool skill install [<host>]`)
PASS	`skill install --all` for multi-runtime install
PASS	`skill update` / `skill upgrade` for bundle refresh

Details

Version scored: 1.3.14
Audit date: 2026-06-01 17:35:29 UTC
Duration: 339ms
Platform: linux/x86_64
Mode: command
Anc build: 0.5.0
Install: brew install bun

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Reproduce this scorecard for bun locally and inspect the failing audits:

anc audit --command bun --output json

Install anc first if you don't have it. Add --output json to get the same JSON shape committed under scorecards/.