ADR 0009 — AgentValidation placement

• Status: Accepted
• Date: 2026-06-02
• Decision source: the V3 modular-distribution implementation plan (docs/reports/2026-06-02-v3-modular-distribution-implementation-plan.md, §0.4 + Stage 2) and feature 048-v3-retirement-baseline (research.md D8).

Context

src/Lib/AgentValidation.fs(i) (835 + 261 LOC) is a governance/agent-contract parser that lives inside the runtime monolith for no runtime reason — it parses and validates agent-facing contracts, which is build/governance concern, not rendering. The before-baseline (docs/reports/_baselines/2026-06-02-v3-before.md §6) confirms the build front-end (build/Governance/Front/Support.fs) no longer consumes it (the governance library already owns CapabilityRow/ValidationFinding); the remaining consumer is tests/Governance.Tests/AgentValidationFrameworkTests.fs. So the surface is a governance artifact stranded in the runtime monolith.

Decision

*AgentValidation moves into the FS.Skia.UI.Build governance library.* It leaves the runtime monolith entirely; its test (AgentValidationFrameworkTests) repoints onto the governance-library home. No runtime package gains or keeps an agent-validation surface.

Alternatives considered

• Leave AgentValidation in a surviving runtime split package (rejected). It is not a rendering concern; placing it in Scene/SkiaViewer would smuggle governance code into the runtime distribution.
• Delete it outright (rejected). It is still exercised by a governance test and is a real contract-validation surface; relocation, not deletion, is correct.

Rationale

Governance code belongs in the governance library (FS.Skia.UI.Build, ADR 0001). Relocating AgentValidation removes ~1,096 LOC from the monolith and is independent of the host move, so it can proceed in parallel after the keystone.

Affected stages

• Stage 2: relocate AgentValidation into FS.Skia.UI.Build; repoint its test.