LSP Context Injection

Feature flag: lsp-context (included in --features full)

LSP Context Injection automatically adds compiler-derived information to the agent’s context after certain tool calls — without the LLM needing to issue explicit tool requests.

What It Does

Three hooks fire automatically during a conversation:

Hook	Trigger	What gets injected
Diagnostics	After `write_file`	Compiler errors and warnings for the saved file
Hover (opt-in)	After `read_file`	Type signatures for key symbols in the file
References	Before `rename_symbol`	All call sites of the symbol being renamed

The injected data appears as a [lsp ...] prefixed message in the conversation history — the same pattern used by semantic recall and graph facts. A per-turn token_budget cap prevents runaway context growth.

Why It Matters

Without this feature, the agent has to explicitly call get_diagnostics, get_hover, or get_references after every file operation. With LSP Context Injection enabled, the feedback loop is automatic:

Agent writes a file.
Zeph fetches diagnostics from the language server.
Errors appear as the next turn’s context — the agent fixes them immediately.

No extra round-trips. No “check for errors” prompt needed.

Prerequisites

mcpls configured as an MCP server (see LSP Code Intelligence)
lsp-context feature enabled (already included in the full feature set)

Enabling

# For a single session
zeph --lsp-context

# Or set permanently in config.toml

[agent.lsp]
enabled = true

The interactive wizard (zeph --init) prompts for this setting after the mcpls step.

Graceful Degradation

When mcpls is unavailable, all hooks silently skip. The agent continues working normally — no errors are shown, no functionality is lost. Individual failures are logged at debug level only.

Configuration and Details

Full configuration reference, token budget tuning, and TUI status command: LSP Context Injection → guides/lsp.md

For IDE-proxied LSP via ACP (Zed, Helix, VS Code): ACP LSP Extension → guides/lsp.md

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