2026-10-22 — The merge gate's footprint is step-wise (abcd-ae's ruling as coordinator of 2026-10-23, spc-2610161609350616, itd-2610150602547271, following the worktree store's dcn-2610222227336378): the build reserves at start only the files steps 1-3, 5 and 6 change, leaving out internal/core/implement/loop/land.go and its test, which only step 4 changes and which the drain's reservation of iss-2610120138028442 holds while that lane waits for its preflight, and internal/surface/cli/cli.go, which only step 2 changes and which iss-2610171110154902 and iss-2610171200535090 hold until 2026-10-23T08:40Z; when the step that changes a left-out file begins, the spec's packages line widens to name it and a re-run of abcd build reserves the widened footprint (the verb reserves again when the spec has widened, per commands/build.md), judged for overlap like any reservation. Steps 4 and 6 still land as one change. <!-- record-lint: forward-looking -->

Frontmatter

.abcd/work/decisions/dcn-2610222356532638-the-merge-gate-s-footprint-is-step-wise.md
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mentions7

• dcn-26102222273363782026-10-22 — The worktree store's footprint is narrowed to the files its steps change (abcd-ae's ruling as coordinator of 2026-10-22, spc-2609301811532881, itd-2609091014076309): the spec's footprint named whole packages, among them internal/core/implement/loop and internal/surface/cli, which the merge gate's spec also names, so the first to reserve would have held the other off for days; each spec now names the files its steps' packages and tests lines change, read from those lines and never guessed narrow, and a file still in both after narrowing goes to the merge gate first, the store sequencing its step on that file after the merge gate lands; agreed with abcd-43 the same night: internal/core/board/board.go and its test, internal/surface/cli/cli.go and internal/surface/cli/board.go are the merge gate's first, so the store's footprint leaves them out until the merge gate lands and its steps 2 and 6, which need them, are not driven before then, the footprint then widening to take them; and the generated docs/reference/cli/commands.md and .abcd/development/release/surface.json are reserved by neither spec, since they derive from the code and whoever lands second regenerates them; and since other live lanes hold the brief and command-page files only step 7 needs, the footprint names step 1's files first and widens as each step is reached, which the build's reservation supports by reserving again with the widened footprint (grounds: AGENTS.md concurrent sessions, reserve with the footprint the work will change; the reservation's overlap rule)
• dcn-26102301293312322026-10-23 — The model matrix's build footprint is step-wise and by file (abcd-ae's ruling as coordinator of 2026-10-23 for spc-2610161949559050, itd-2610161733316518, following dcn-2610222227336378 and dcn-2610222356532638): the spec's packages line named whole packages (internal/core/implement/loop, internal/core/runner, internal/core/oracle, internal/surface/cli and others) that the merge gate's, the worktree store's and abcd-f1's pin and route builds also change, so a directory reservation would hold them all for the days the matrix takes. The build reserves at start only step 1's sixteen files (the new internal/core/matrix package, internal/core/lab/procedure.go and its test, internal/core/lab/preflight.go, internal/README.md and ACKNOWLEDGEMENTS.md); each later step's files join the packages line when that step begins, and abcd build then reserves the widened footprint, judged for overlap. Generated output is reserved by no one. <!-- record-lint: forward-looking -->
• iss-2610120138028442The implement loop's merged check (internal/core/implement/loop/land.go, landMerged) asks the forge twice per poll while a pull request is not merged: `gh pr view --json state`, then prMergeability's `gh pr view --json mergeable,mergeStateStatus`. Both fields come from one view, so each poll spends two forge calls where one would answer, against the same rate limit the loop's other waits share.
• iss-2610171110154902A host approval prompt for a shell command stalls an autonomous run. The host asks the person to approve a command it cannot check (an unread script, a compound line), and with nobody at the terminal the run waits until someone returns. Auto-approving a repeat was considered and rejected: it lets any agent past every check by retrying, so the refusal is repeated every time instead and the agent is told how to rewrite the command.
• iss-2610171200535090A person cannot mark a hand-steered session as autonomous. The approval-prompt refusal turns on only while abcd's own build or drain runs, so a session the person tells to work alone and leaves still stalls on the host's approval prompts. The product thinker named a switch on the mode verb as the likely shape.
• itd-2610150602547271The facilitator's mode gates the merge
• spc-2610161609350616The facilitator's mode gates the merge