lsp: split monolithic server.go into modules; add configurable max tokens and context strategies (minimal|window|file-on-new-func|always-full); provide flags/env fallbacks; add unit tests for helpers and context; update README; remove obsolete files

1 files changed, 30 insertions, 1 deletions

diff --git a/README.md b/README.md
index 8fd42bd..aad155f 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 
 Hexai, the AI LSP for the Helix editor.
 
-At the moment this project is only in the brainstorming phase.
+At the moment this project is only in the proof of concept phase.
 
 ## LLM provider
 
@@ -17,3 +17,32 @@ code completion when `OPENAI_API_KEY` is present in the environment.
 
 If no key is configured, Hexai will fall back to a basic, local completion.
 
+## CLI usage and configuration
+
+- Run LSP server over stdio:
+  - `hexai -stdio`
+
+- Completion settings:
+  - `-max-tokens`: maximum tokens for LLM completions (default `500`). If the flag isn’t provided, `HEXAI_MAX_TOKENS` is used when set.
+  - `-context-mode`: how much additional context to include with completion prompts. One of:
+    - `minimal`: no extra context
+    - `window`: include a sliding window around the cursor
+    - `file-on-new-func` (default): include the full file only when defining a new function (cursor before the opening `{`)
+    - `always-full`: always include the full file (may be slower/costly)
+  - `-context-window-lines`: line count for the sliding window when `context-mode=window` (default `120`).
+  - `-max-context-tokens`: budget for additional context tokens (default `2000`). If the flag isn’t provided, `HEXAI_MAX_CONTEXT_TOKENS` is used when set.
+
+Notes:
+- Token estimation for truncation uses a simple 4 chars/token heuristic.
+- Full-file context is only included by default when defining a new function to balance quality, latency, and cost.
+
+### Flags quick reference
+
+| Flag                    | Default            | Env override               | Description                                        |
+|-------------------------|--------------------|----------------------------|----------------------------------------------------|
+| `-stdio`                | `true`             | —                          | Run as LSP over stdio (only supported mode).       |
+| `-log`                  | `/tmp/hexai.log`   | —                          | Path to log file (optional).                       |
+| `-max-tokens`           | `500`              | `HEXAI_MAX_TOKENS`         | Max tokens for LLM completions.                    |
+| `-context-mode`         | `file-on-new-func` | —                          | `minimal` `window` `file-on-new-func` `always-full` |
+| `-context-window-lines` | `120`              | —                          | Lines around cursor when using `window` mode.      |
+| `-max-context-tokens`   | `2000`             | `HEXAI_MAX_CONTEXT_TOKENS` | Token budget for additional context.               |