Make the neutral core boundary real: src/core imports nothing from pi

[rgarcia]

Summary

Phase 5d: make the neutral boundary real. src/core now imports nothing from pi — runtime or type-only — and an automated check enforces it. The . and ./pi export surfaces are unchanged in behavior: provider-qualified refs, tool identities, model-facing names, and catalog.model semantics (including object identity when nothing is derived) all work exactly as documented.

Neutral types in core

• LoopToolDeclaration (core/tool-catalog.ts): { name, description, parameters: TSchema } replaces pi-ai's Tool in specs, catalog entries, and catalog.toolDeclarations. Structurally still a pi-ai Tool, so pi consumers are unaffected.
• LoopExecutableTool / LoopToolExecutionResult (core/resources.ts): materialize(spec) returns { spec, execute(input, signal) } with neutral text/image content blocks. The pi wrapper shape (toolCallId, label, executionMode, AgentTool) lives in the pi tool manager's adapter, cached per executable so recompiles keep stable tool identity.
• LoopCatalogModel / LoopModelFacts (core/model-info.ts): the compiler and menu see only { provider, id, api } plus binding-supplied availability facts (capabilities, nativeSurfaces) and model-preparation payload transforms passed as compile inputs. The pi binding derives facts from its registry/quirk tables (loopModelFacts()) and contributes the Anthropic thinking-budget transform (loopModelPreparationTransforms()); core only orders and validates what it is handed. This also removed core's provider-name payload branch.
• LoopCompiledModel<M>: catalog.model is typed as the input model with api widened to string (compilation may derive a tool's required transport onto it), so the generic output type is honest without casts.

Schema builder decision

Core imports Type/TSchema from typebox@1.3.7 directly — the exact package and version pi-ai depends on and re-exports. npm dedupes to a single instance, so TSchema identity is unchanged for every consumer; parameters flow to the catalog exactly as before.

File moves

• core/tool-manager.ts → src/pi/tool-manager.ts (joins compiled catalogs to executable pi AgentTools — genuinely pi-coupled).
• pi/providers/anthropic/native.ts → core/anthropic-native.ts: the pure input→canonical-action mapper is the execution half of core-declared specs, the same category as the OpenAI/Google mappers already in core/tools.ts. Stream/wire adapters all remain in src/pi/providers/.
• modelSupportsDeferredTools → pi/models.ts (interprets pi compat flags); Anthropic native version gates stay in pi/providers/anthropic/capabilities.ts; the published loop namespace is composed in pi/loop.ts, layering loop.providers.anthropic.supports over core's declarations.
• Loop-owned api id constants (OPENAI_COMPUTER_USE_API, GOOGLE_INTERACTIONS_API) moved next to their consumer in core/tool-catalog.ts; transport routing stays in src/pi/providers.ts.
• New src/pi/catalog.ts: ref-accepting compileLoopToolCatalog/loopToolMenu wrappers; explicit exports in src/index.ts shadow the core star exports so the . surface keeps accepting "provider:model" refs.

Enforcement

test/core-boundary.test.ts runs in the normal unit suite and walks every src/core/**/*.ts import/export-from/dynamic-import/require specifier with statement-anchored extraction. It default-denies: only core-relative paths and an allowlist of neutral bare imports (node:, typebox, @onkernel/sdk, sharp) pass. @earendil-works/*, @onkernel/loop, @onkernel/loop/pi, and any future alias fail, runtime or type-only. Verified red against probe files before landing.

Testing

• npx tsc -b --force clean across the workspace.
• npm test (loop): 33 files, 426 tests passed — the 420 at main plus new coverage for the boundary check, the AgentTool adapter seam, and the facts/preparation compile inputs.
• Built package smoke-tested: string-ref compilation, menu availability (including native entries), and loop.providers.anthropic.supports.browser behave identically on dist.
• Integration/live suites not run locally (they need a Kernel browser and provider keys); CI's integration job covers them.

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Note

Medium Risk
Touches catalog compilation, tool materialization, and public export surfaces across core and pi; behavior is intended to be unchanged but the refactor spans critical agent-tool wiring.

Overview
Makes src/core a real framework-neutral layer by removing all pi / pi-ai imports and introducing neutral types the pi binding wraps at the edges.

Core now owns LoopToolDeclaration (schemas via typebox), LoopExecutableTool / LoopToolExecutionResult (execution is (input, signal) only), and LoopCatalogModel / LoopModelFacts so catalog compilation and the tool menu no longer resolve models or look up provider capabilities in core. The pi side supplies loopModelFacts(), loopModelPreparationTransforms() (e.g. Anthropic adaptive thinking), and ref-accepting compileLoopToolCatalog / loopToolMenu wrappers in pi/catalog.ts.

Moves pi-coupled code out of core: tool manager → pi/tool-manager.ts (with a cached AgentTool adapter), Anthropic native input mapping → core/anthropic-native.ts, modelSupportsDeferredTools → pi/models.ts, and the published loop namespace gains providers.anthropic.supports from pi/loop.ts.

Adds test/core-boundary.test.ts to fail the unit suite if any src/core file imports outside an allowlist (no pi packages, no @onkernel/loop/pi). Public . behavior is preserved via explicit re-exports that shadow core for string model refs and composed loop.

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