site/content/docs/prior-art/index.md

-description: "What already exists, and what zz borrows or diverges from, explicitly."

-What already exists, and what **zz** borrows or diverges from, stated explicitly rather than left implicit.

-The **Contract Net Protocol** (Reid G. Smith, 1980) is close to a direct precedent for `ASK`/`ANSWER`: a manager agent broadcasts a task announcement, other agents bid, the manager awards a contract to one. `ASK`-as-work-offer and `ANSWER`-as-claim are a production implementation of a fifty-year-old, well-studied pattern.

-**Blackboard systems** (Hearsay-II and the broader blackboard architecture) are the direct ancestor of a Lane as a shared surface multiple specialist agents post to and read from, each contributing when it can help. The same pattern also explains why the agents in [the incident this project is named after](/docs/name-and-background/) converged on a message board unprompted: a well-known architecture, independently rediscovered.

-**Gerrit** already has a close analog to Changeset: a "Change" is the reviewable unit, reviewers score it on labeled categories, and it becomes submittable once it clears its labels with no **veto vote** in any category, Gerrit's own term. That's independent, production validation that Changeset and `VETO` land on the right shape.

-Bors and GitHub's Merge Queue solve concurrent landings by **serializing**: test each change against the current base one at a time, merge if green, move to the next. OCC diverges from this deliberately: non-overlapping changes merge in parallel rather than queueing behind each other, the throughput OCC exists to provide at agent scale.

-That divergence has a real limit: OCC proves only the absence of *mechanical* conflicts: overlapping symbols or lines. Two Changesets that touch disjoint code but are behaviorally incompatible together clear OCC's fast path and silently break something, a *semantic* conflict OCC was never checking for. A queue-shaped mechanism still exists for this, demoted from the primary gate to a periodic backstop: a recurring Lane that re-validates a batch of recently merged Changesets together, triggered on a cadence or by a Tripwire when merge density in some scope crosses a threshold, with `ROLL` as the recovery path on failure. High-contention files need no special handling either. A hotspot simply never clears OCC's fast path, so review concentrates exactly where it already belongs without serializing the rest of the repo.

-## Is OCC itself novel?

-Partially, and it's worth being precise about which part. Git's own merge has been optimistic from the start: it proceeds without locking and checks for conflict only at merge time. Git detects conflict at the **text-line level**, though, which produces both false positives (unrelated edits that happen to sit near each other in a file) and false negatives (edits on different lines that are semantically incompatible merge silently). Moving the unit of conflict detection to the **dependency graph's symbols** instead of text lines is the same move build systems like Bazel and Pants already made for change-impact analysis, tracing the graph instead of diffing text. Structural, AST-aware merging is already a shipping product in Plastic SCM's **SemanticMerge**. And the term itself predates all of this: Kung and Robinson's 1981 paper on optimistic concurrency control describes read/write-set validation at transaction-commit time in databases, structurally identical to what happens here, applied to code instead of rows.

-What's new is combining these three ideas (optimistic merging, graph-based impact analysis, structural conflict detection) into the mechanism that drives an agent coordination fast path specifically, wired into Lane, Claim, Trust, and Tripwire, rather than any one of the underlying techniques on its own.

-Four real precedents inform Vote, lazy consensus, and the Committee model in [Governance](/docs/governance/#committee):

-- **The Apache Software Foundation**: lazy consensus (propose, silence-is-assent) as the default, with a formal Vote only for decisions that need one. zz's ballots (`+1`/`+0`/`-0`/`-1`) are ASF's own.

-- **Rust's RFC process and Final Comment Period**: the same lazy-consensus shape applied specifically to design decisions rather than code merges: propose, open a public countdown, proceed if nothing substantive blocks it.

-- **IETF's "rough consensus and running code"**: an older, more famous instance of the same idea, predating both.

-- **Debian's constitution**: supermajority requirements that scale with what's being decided (simple majority for routine resolutions, higher thresholds for overriding a maintainer or amending the constitution itself), the direct precedent for Vote's threshold varying by decision type.

-One more, for sharded coordination specifically: **the Linux kernel's subsystem-maintainer tree**, where each subsystem maintainer merges independently into their own tree, flowing up through a hierarchy to Linus. It's evidence the sharded-Coordinator pattern scales to one of the largest codebases that exists.

-**Phabricator's Herald** (declarative "when X, take action Y" automation rules) is close to Tripwires, but the fuller comparison, including policy-as-code tools like Open Policy Agent and GitHub Actions/Danger-style PR automation, belongs with the Tripwire implementation work.