How-To Series · Module 7: Power Tools
LSP: Semantic Diagnostics
Real language servers catch type errors the instant a file is written.
After this videoYour agent sees the same type errors a coding agent in an IDE would
Hermes runs full language servers like pyright, gopls, rust-analyzer, and typescript-language-server as background subprocesses and feeds their semantic diagnostics into the post-write lint check used by write_file and patch. After every edit, the agent sees exactly the errors that edit introduced: type errors, undefined names, missing imports, and project-wide semantic issues. LSP is gated on git workspace detection, layered with a syntax-only fallback, and configurable per-server in config.yaml.
About these resources. This episode explains the LSP subsystem in Hermes. The Sources block names the Hermes docs page that backs every claim.
New words here · Plain English
one sentence each · full glossaryLanguage ServerA background program that understands a programming language and can point out errors in your code, like a spellchecker for code.
LSPLanguage Server Protocol. A standard way for editors and tools to talk to language servers without being tied to one specific editor.
Semantic diagnosticsErrors that go beyond syntax, like using a variable that does not exist or passing the wrong type to a function.
PyrightA language server for Python, made by Microsoft. It catches type errors and undefined names.
Sources · What this video distills
1 docs page · every command below traces to one of themCommands shown · Copy and paste
each shows the source doc it came fromhermes lsp statushermes lsp install pyrighthermes lsp install-allhermes lsp restart