Timeline

`mv --help` advertises `zit mv NEW OLD` as the way to undo a rename, so it is the sequence a user is most likely to run. It left the pending record replaced rather than cleared: OLD->NEW->OLD queued a §4.7.6 old-name F card asserting OLD was formerly NEW -- a name no manifest has ever carried. The next commit with any real change would write that false claim about the past into a permanent artifact, where it cannot be taken back. A rename and its inverse are a no-op, so the pair now nets the record out.

This survived the guard because the guard's oracle was indirect: commit reports "nothing to commit" on CONTENT alone, so a stranded record passes it silently and surfaces only at the next commit that carries a change. The record is now read back directly.

mv's move errors render through `reasonOf` rather than `@errorName`, so EACCES reads "permission denied" instead of "AccessDenied". This was deferred as errno-sweep work, but the mapping already exists and `init` and `clean` print through it -- reuse, not new scope. A raw Zig error name is an internal identifier, not a diagnostic. closed check-in: 7235a86bcd user: dmestas tags: blockers

`tag` was read-only: `tag list` was the only subcommand, so a repository could not be given a name for a check-in at all (blocker B6). The verb told the truth about what existed, but the capability was simply absent.

WHAT CHANGED

`zit tag add NAME CHECKIN` mints one CONTROL artifact carrying a single `T +sym-NAME` card targeting the resolved check-in's 64-hex hash.

THE SIGN IS THE WHOLE CORRECTNESS ARGUMENT. The card is a SINGLETON (`+`), not a propagating (`*`) tag. `repostate.resolveName` (src/repostate.zig:891) picks the max-`event.mtime` check-in among ALL active `sym-` rows, so a propagating `*sym-v1` would be inherited by every descendant and then resolve to the NEWEST of them — the name would silently drift off the check-in the user tagged, which is the same class of wrong answer as B1. `applyTagOps` (src/repostate.zig:727) gates propagation on `op.type != .singleton`, so a `+` card pins the name with ZERO repostate changes. The contrast with a branch is deliberate and now documented at both sites: a *branch* sym propagates precisely because descendants must inherit it; a *tag* sym does not, precisely because they must not.

`amend`'s steps 5-6 — assemble the control manifest, run the runtime-safety round-trip self-check, `putArtifact` + `commit` under the single fsync — are extracted into `mintControlArtifact`, and `tag add` is its second consumer. Both verbs resolve a check-in, compose a T run, then mint; that last step is now written once. amend's existing battery guards the extraction unchanged. The helper's error set is `logstore.OpenError`, the widest of the three the body can produce, so each verb renders it under its own name.

`tag add` closes its read view BEFORE the read-write append (commit's durability pattern), so it owns its repository lifetime rather than sharing the listing path's `defer repo.deinit`. Resolution and the empty-NAME check both precede the mint: a run that cannot resolve its CHECKIN mints nothing, asserted by a test.

`selectInheritedSyms`'s comment said zit mints no singleton syms itself, so the §6.2 exclusion of them from a branch move's cancel set was reachable only via a synced `T +sym-X *`. That is no longer true — the comment is corrected. The behavior needed no change, and its unit test already covered a singleton sym.

RECORDED, NOT ASSUMED: branch creation shares no read-only gap. It is already served by `commit --branch`, which mints the propagating branch/sym pair directly on the check-in manifest (src/cli.zig `composeCommitTags`), so there is no `branch add` to write. Cancel/remove semantics stay deferred to 0.2 — closing "cannot create tags" is the blocker; a full tag lifecycle is not.

RED PROOF (per BLOCKER-FIX-PLAN.md section 2, no product code changed until RED was proven; markers `// REGRESSION B6:`)

End-to-end, src/e2e.zig — all five failed pre-fix at `tag add` with exit 2 ("unknown subcommand 'add'"):

cli REGRESSION B6: tag add creates a tag that tag list and tag list CHECKIN report cli REGRESSION B6: a created tag pins to its check-in and is not inherited by a descendant (tag before commit) cli REGRESSION B6: a created tag pins to its check-in and is not inherited by a descendant (commit before tag) cli REGRESSION B6: a created tag survives pack cli REGRESSION B6: a created tag survives a clone

The pinning pair runs both orderings — tag-then-commit exercises inheritance at commit time, commit-then-tag exercises the propagation walk over already crosslinked descendants. Identical behavior in both is what proves the mechanism rather than luck. pack and clone prove the round trip: a synced artifact that does not survive sync is a worse lie than a missing verb.

Added alongside them: `tag add`'s arity errors, and an unresolvable CHECKIN leaving no tag behind. Unit, src/cli.zig: the parser's add grammar (both positionals required, `--help`/bad option winning over arity, `--` handling), `composeTagAddCards` minting exactly one `+sym-` card at the target, its control round trip through `artifact.parse` proving the sign survives the wire, and leak-freedom under `checkAllAllocationFailures`.

TEST EVIDENCE NOW

In this worktree at the committed tree: `zig fmt --check .`, `zig build`, `zig build test`, and `zig build e2e` each exit 0 — full battery, no filtering.

CHANGED EXPECTATIONS (both encoded the missing capability, nothing else)

cli tag B-tag-7 (src/cli.zig) and cli tag B-tag-13 (src/e2e.zig) used the literal token `add` as their stand-in for "not a subcommand". `add` IS one now, so both use `cancel`, a word that still is not.

cli tag B-tag-11's verbatim `tag_help_expected` gains the `add` usage line and its paragraph, because `tag --help` must teach the new grammar.

No borrowed technique: the singleton-sign argument and the mint extraction are original to this change. No performance claim is made.

SIBLING MERGE

This checkout absorbed the sibling B3 commit (1aeb531cac) before landing. The only conflict was in src/e2e.zig and was positional, not semantic: both changes append a new regression block at the end of the file. Both blocks are kept, one copy each; the two candidate B3 hunks fossil presented were byte-identical, and the full battery above was re-run on the merged tree, not just on mine. check-in: d8e5e8117d user: dmestas tags: blockers