---
id: PLN-0115
ticket: multi-frontend-remove-pbs-branches
title: Migrate signature help to generic frontend models
status: done
created: 2026-07-15
completed: 2026-07-15
ref_decisions: [DEC-0042]
tags: [compiler, compiler-general, compiler-pbs, studio, frontend, coupling, multi-frontend]
---

## Briefing

`DEC-0042` requires signature help to be exposed through generic frontend models rather than PBS-specific editorial models.

## Objective

Migrate LSP signature help handling to generic frontend signature-help models while preserving PBS callable labels, parameter labels, active signature, and active parameter behavior.

## Dependencies

- Depends on `PLN-0111`.
- Should run after `PLN-0114` because hover and signature help may share generic signature DTOs.

## Scope

- Map PBS signature help to generic `FrontendSignatureHelp` and `FrontendSignature`.
- Update LSP signature-help mapping to consume generic models.
- Preserve deterministic empty signature help when unsupported.

## Non-Goals

- Changing PBS callable resolution.
- Changing parameter-name semantics.
- Adding parameter documentation beyond existing behavior.
- Removing all PBS imports from LSP if other capabilities are still pending.

## Execution Method

1. Inspect current `PBSFrontendLanguageService.signatureHelp(...)` and `PbsEditorialSignatureHelp`.
2. Ensure generic `FrontendSignatureHelp` represents signatures, active signature, active parameter, labels, and parameter labels.
3. Add PBS mapping to generic signature help inside the PBS frontend boundary.
4. Update `CompilerLanguageServiceBridge.signatureHelp(...)` to call generic signature-help capability.
5. Preserve empty response behavior for absent language service or absent signature-help capability.
6. Verify completion/hover shared signature models still satisfy their tests.

## Acceptance Criteria

- LSP signature help no longer consumes PBS-specific signature-help types.
- PBS signature-help output remains stable.
- Active signature and active parameter are preserved.
- Compile-only providers receive deterministic empty signature help.

## Tests

- PBS signature-help/editorial tests.
- LSP signature-help bridge tests.
- Missing capability fallback tests.
- Regression tests for callable parameter labels.

## Affected Artifacts

- `prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/services/...`
- `prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/PBSFrontendLanguageService.java`
- `prometeu-lsp/prometeu-lsp-v1/src/main/java/p/studio/lsp/services/compiler/CompilerLanguageServiceBridge.java`
- Signature-help tests.