jj

A Git-compatible VCS that is both simple and powerful

workhorse Rust martinvonz/jj
75% 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.

LevelTotalVerifiedUnverified
MUST28199
SHOULD21138
MAY10100

Top Issues

All Audits

P1: Non-Interactive by Default

PASSNon-interactive by default
SKIPNon-interactive gate flag advertised in --helptarget satisfies P1 via alternative gate (help-on-bare or stdin-primary)
WARNFlags advertise env-var bindings in --help14 flag(s) found in --help but no `[env: NAME]` bindings advertised
PASSSecret-bearing flags expose stdin or *-file companion
WARN`--help` advertises default values for flagsno default-value annotations found in --help. SHOULD-tier — agents reading help text need to see what value a flag falls back to when omitted (`[default: <value>]` per clap convention).
PASSRich-TUI affordance for TTY contexts

P2: Structured, Parseable Output

OPT-OUTStructured output supportno --output/--format flag detected in any subcommand — tool does not ship structured output.
N/AStructured-output CLI exposes its schema at runtimeantecedent `p2-json-output` is opt_out: no --output/--format flag detected in any subcommand — tool does not ship structured output.
WARN--json / --jsonl short aliases for --outputno --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 outputno `--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/jsonno `--output` or `--format` flag advertised; vacuous skip for MAY-tier extra formats.
PASSBad invocation exits with structured usage-error code (2)
SKIPErrors 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.
SKIPJSON success and error envelopes share their non-payload key setbinary does not advertise `--output json` in --help; envelope-consistency only applies to CLIs that opt into the JSON contract.

P3: Progressive Help Discovery

PASSHelp flag produces useful output
PASSVersion flag works (`--version` plus short alias)
PASSVersion flag works (`--version` plus short alias)
WARN`examples` subcommand or `--examples` flag for curated usage patternsno `examples` subcommand or `--examples` flag found. MAY-tier — a curated usage block keeps agents from hunting through long help text.
PASSShort `-h` summary differs from `--help` long form
FAILEach subcommand's `--help` ships at least one invocation examplesubcommands missing example invocations in their `--help`: abandon, absorb, arrange, bisect, bookmark, commit, config, describe, diff, diffedit, duplicate, edit, evolog, file, gerrit, git, log, operation, redo, resolve, restore, revert, root, show, sign, simplify-parents, sparse, squash, status, tag, undo, unsign, util, version, workspace. Examples teach agents the call shape faster than option tables; use clap's `after_help` or a dedicated `Examples:` block.
WARNHelp text pairs human and `--output json` example invocationsno 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

PASSRejects invalid arguments
PASSError messages include a hint or remediation phrase
SKIP`--output json` produces JSON-formatted errorsbinary does not advertise `--output json` in --help; SHOULD applies only to CLIs that opt into the JSON contract.

P5: Safe Retries & Mutation Boundaries

SKIPDestructive subcommands require `--force` or `--yes`no destructive subcommands detected; MUST applies conditionally to CLIs with destructive operations.
WARNRead and write surfaces are both visible in subcommand listread-pattern subcommand(s) present (show) but no write-pattern surface detected. If the CLI is read-only by design the MUST is satisfied vacuously; otherwise the write surface needs an agent-recognizable verb (create/add/update/set/delete/…).

P6: Composable, Predictable Command Structure

PASSHandles SIGPIPE gracefully
PASSPager-using CLI ships --no-pager escape hatch
PASSRespects NO_COLOR
WARNSubcommand verbs follow community-standard names7/45 subcommand(s) follow standard verb names. Non-standard: abandon, absorb, arrange, bisect, bookmark, commit, diffedit, duplicate, edit, evolog, file, fix, gerrit, git, interdiff, log, metaedit, new, next, operation, parallelize, prev, rebase, redo, resolve, restore, revert, root, sign, simplify-parents, sparse, split, squash, tag, undo, unsign, util, workspace. MAY-tier — community-standard verbs (get/list/create/update/delete) help agents predict subcommand behavior across CLIs.
PASS`--color` flag for explicit color control
SKIPInput-accepting commands read from stdin when no file is givenno input-accepting subcommand detected (process/parse/convert/transform/analyze/validate/format/lint/audit); vacuous skip for the conditional SHOULD.
WARNSubcommand naming follows a consistent verb/noun conventionsubcommand naming is inconsistent: 7 non-verb subcommand(s) (bookmark, config, file, git, operation, sparse, workspace) mix verb and non-verb children at the second level, so an agent cannot predict where the action lives. SHOULD-tier: pick a consistent shape (all verb-first, all noun-verb hierarchy, or any combination where each non-verb group's children are uniformly verbs). The verb list is a heuristic; inspect `--help` to confirm.
PASSOperations are subcommands, not verb-shaped flags

P7: Bounded, High-Signal Responses

PASSQuiet mode available
WARN`--verbose` flag for diagnostic escalationno `--verbose` / `-v` flag advertised. SHOULD-tier — agents debugging failures need a way to escalate diagnostic detail.
WARN`--limit` / `--max-results` flag for list operationslist-style subcommand present but no limit flag advertised (looked for --limit, --max-results, --max, --top, -n). SHOULD-tier — callers should be able to bound response size directly rather than scrape-then-truncate.
WARNCursor-based pagination flags for list traversallist-style subcommand present but no cursor/page flag advertised (looked for --after, --before, --cursor, --page, --offset). MAY-tier — cursor pagination lets agents traverse large result sets without re-scanning earlier pages.
SKIP`--timeout` flag for long-running operationsno long-running subcommand detected (serve/daemon/watch/tail/monitor/follow/run/start/stream); vacuous skip for the conditional SHOULD.
WARNHelp text advertises TTY-aware verbosity behaviorno 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

PASSSkill 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
0.41.0
Audit date
2026-06-01 17:34:31 UTC
Duration
538ms
Platform
linux/x86_64
Mode
command
Anc build
0.5.0
Install
brew install jj

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