FE-524: Add Inhibitor Arc support

[alex-e-leon]

🌟 What is the purpose of this PR?

Adds inhibitor arcs to petrinaut. Specifically this:

• adds a new "type: 'inhibitor' | 'standard' field to input arcs
• updates the logic for executing a net with inhibitor arc logic
• styles inhibitor arcs with a dot-dash line + circle endpoint
• adds a new "deployment pipeline" example net to the examples folder with an inhibitor arc added.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• modifies an npm-publishable library and I have added a changeset file(s)

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

• do not affect the execution graph

⚠️ Known issues

The new circle markers for inhibitor arcs don't play super nice with the existing arrows for other arcs. Currently if there is an inhibitor arc, any standard arc arrows are hidden by the new circle marker. We will likely need to rethink how we show markers/connections down the line.

The new dashed stroke style is also possibly confusing. Based on some quick research, it looks like "conditional arcs" also use a dashed line style. I've adjusted the stroke to be a dot-dash pattern to make it less confusing, but it may still not be a great style.

[cursor]

PR Summary

Medium Risk
Updates core SDCPN data structures and simulation enablement/execution logic to support inhibitor arcs, which could change net behavior and rendering if any assumptions about input arcs were implicit. Backward compatibility is mostly handled via schema defaults, but existing serialized nets/clipboard payloads rely on that defaulting behaving correctly.

Overview
Adds inhibitor arcs support end-to-end. Input arcs now carry a type (standard/inhibitor) in core SDCPN types plus clipboard and file-format schemas (defaulting to standard for backward compatibility).

Simulation behavior changes: transition structural enablement and firing now treat inhibitor arcs as guards (tokens < weight) and they no longer contribute tokens to transition inputs or token consumption; LSP virtual input types also ignore inhibitor arcs.

Editor + examples updates: the arc properties panel can toggle input-arc type, inhibitor arcs render as dashed edges with a circle marker, and a new “Deployment Pipeline” example net demonstrates inhibitor usage; existing tests/examples were updated to include type: "standard" on input arcs.

^{Reviewed by Cursor Bugbot for commit 0647a99. Bugbot is set up for automated code reviews on this repo. Configure here.}

[vercel]

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Project	Deployment	Actions	Updated (UTC)
hash	Ready	Preview, Comment	Apr 13, 2026 1:03pm
petrinaut	Ready	Preview, Comment	Apr 13, 2026 1:03pm

2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
hashdotdesign	Ignored	Preview	Apr 13, 2026 1:03pm
hashdotdesign-tokens	Ignored	Preview	Apr 13, 2026 1:03pm

[augmentcode]

🤖 Augment PR Summary

Summary: This PR adds inhibitor-arc support to Petrinaut SDCPN nets, including persistence, simulation semantics, and UI rendering.

Changes:

• Introduces an explicit type field on input arcs (standard | inhibitor) and updates core SDCPN typings accordingly.
• Updates clipboard and file-format Zod schemas to accept the new field and default missing arc types to standard for backwards compatibility.
• Extends simulator enablement logic so inhibitor arcs enable when tokenCount < weight, and updates firing logic so inhibitor arcs are not consumed.
• Adds unit tests for inhibitor-arc enablement and firing behavior.
• Updates the editor properties panel to allow changing an arc’s type, and adds visual styling for inhibitor arcs (dot-dash stroke + circle end marker).
• Adds a new “Deployment Pipeline” example net demonstrating inhibitor arcs, and tweaks SDCPN view zoom padding.

Technical Notes: Inhibitor arcs currently affect marker rendering interactions with existing arrow markers (noted in PR description), and the new arc type is passed through ReactFlow edge data for rendering.

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[augmentcode]

Review completed. 4 suggestions posted.

Comment augment review to trigger a new review at any time.

[kube]

Looks good! Good job!

Only minor thing on making type required on ArcData to force the mapper.

Will check a bit more on Monday after you fixed the AI reviews, but should be good.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

Autofix Details

Bugbot Autofix prepared a fix for the issue found in the latest run.

• ✅ Fixed: Output arcs receive unintended type property from addArc
  • Updated addArc to add type only for input arcs and removed the invalid type field from the output-arc test fixture.

Or push these changes by commenting:

@cursor push ba1e8904d4

Preview (ba1e8904d4)

diff --git a/libs/@hashintel/petrinaut/src/lsp/lib/create-sdcpn-language-service.test.ts b/libs/@hashintel/petrinaut/src/lsp/lib/create-sdcpn-language-service.test.ts
--- a/libs/@hashintel/petrinaut/src/lsp/lib/create-sdcpn-language-service.test.ts
+++ b/libs/@hashintel/petrinaut/src/lsp/lib/create-sdcpn-language-service.test.ts
@@ -113,9 +113,7 @@
         inputArcs: [
           { placeId: "place1", weight: 1, type: "standard" as const },
         ],
-        outputArcs: [
-          { placeId: "place2", weight: 1, type: "standard" as const },
-        ],
+        outputArcs: [{ placeId: "place2", weight: 1 }],
         lambdaCode: "",
         transitionKernelCode: "",
       },

diff --git a/libs/@hashintel/petrinaut/src/state/mutation-provider.tsx b/libs/@hashintel/petrinaut/src/state/mutation-provider.tsx
--- a/libs/@hashintel/petrinaut/src/state/mutation-provider.tsx
+++ b/libs/@hashintel/petrinaut/src/state/mutation-provider.tsx
@@ -126,13 +126,18 @@
       guardedMutate((sdcpn) => {
         for (const transition of sdcpn.transitions) {
           if (transition.id === transitionId) {
-            transition[
-              arcDirection === "input" ? "inputArcs" : "outputArcs"
-            ].push({
-              type: "standard",
-              placeId,
-              weight,
-            });
+            if (arcDirection === "input") {
+              transition.inputArcs.push({
+                type: "standard",
+                placeId,
+                weight,
+              });
+            } else {
+              transition.outputArcs.push({
+                placeId,
+                weight,
+              });
+            }
             break;
           }
         }

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 7692cc7. Configure here.}

[kube]

👍