Language Server CLI Empowers Language Agents with Process Rewards
Large language models routinely hallucinate APIs and mislocalize edits, while
language servers compute verified, IDE-grade facts about real code. We present
Lanser-CLI, a CLI-first orchestration layer that pins and mediates a Language
Server Protocol (LSP) server for coding agents and CI, exposing deterministic,
replayable workflows. Our position is that language servers provide not only
structural information (definitions, references, types, diagnostics) but also
an actionable process reward: machine-checked, step-wise signals that align an
agent's planning loop with program reality. In this work, Lanser-CLI
contributes: (i) a robust addressing scheme beyond brittle "file:line:col" via
a Selector DSL (symbolic, AST-path, and content-anchored selectors) with a
principled relocation algorithm; (ii) deterministic Analysis Bundles that
normalize Language Server responses and capture environment/capability metadata
with stable content hashes; (iii) a safety envelope for mutating operations
(rename, code actions) with preview, workspace jails, and Git-aware,
transactional apply; and (iv) a process-reward functional derived from Language
Server facts (diagnostic deltas, disambiguation confidence, and safe-apply
checks) that is computable online and replayable offline. We formalize
determinism under frozen snapshots and establish a monotonicity property for
the process reward, making it suitable for process supervision and
counterfactual analysis. Project Page:
https://github.com/yifanzhang-pro/lanser-cli
6900310d22d452aac6dd4305
Yifan Zhang
claimed_verified
2025-10-28T15:36:38.913Z
647bf082aba7062fe5c51ca9
https://cdn-avatars.huggingface.co/v1/production/uploads/647bf082aba7062fe5c51ca9/VvKAhQC_LxBcBuy3XROSX.jpeg
Yifan Zhang
yifAI
user
yifAI
6900310d22d452aac6dd4306
Lanser Contributors
Language Server CLI Empowers Language Agents with Process Rewards
Large language models routinely hallucinate APIs and mislocalize edits, while
language servers compute verified, IDE-grade facts about real code. We present
Lanser-CLI, a CLI-first orchestration layer that pins and mediates a Language
Server Protocol (LSP) server for coding agents and CI, exposing deterministic,
replayable workflows. Our position is that language servers provide not only
structural information (definitions, references, types, diagnostics) but also
an actionable process reward: machine-checked, step-wise signals that align an
agent's planning loop with program reality. In this work, Lanser-CLI
contributes: (i) a robust addressing scheme beyond brittle "file:line:col" via
a Selector DSL (symbolic, AST-path, and content-anchored selectors) with a
principled relocation algorithm; (ii) deterministic Analysis Bundles that
normalize Language Server responses and capture environment/capability metadata
with stable content hashes; (iii) a safety envelope for mutating operations
(rename, code actions) with preview, workspace jails, and Git-aware,
transactional apply; and (iv) a process-reward functional derived from Language
Server facts (diagnostic deltas, disambiguation confidence, and safe-apply
checks) that is computable online and replayable offline. We formalize
determinism under frozen snapshots and establish a monotonicity property for
the process reward, making it suitable for process supervision and
counterfactual analysis. Project Page:
https://github.com/yifanzhang-pro/lanser-cli
Lanser-CLI orchestrates Language Server Protocol servers for coding agents and CI, providing deterministic workflows and actionable process rewards based on verified code facts.
Language Server Protocol LSP coding agents CI Selector DSL AST-path content-anchored selectors Analysis Bundles safety envelope preview workspace jails Git-aware transactional apply diagnostic deltas disambiguation confidence safe-apply checks determinism frozen snapshots monotonicity property process supervision counterfactual analysis