feat: add --no-rerank flag to serve and search commands

[Aetherall]

Summary

• Add --no-rerank flag to osgrep serve and osgrep search
• The serve /search endpoint now respects a rerank field in the request body, with the CLI flag as the default

Problem

The serve command hardcodes { rerank: true } when calling searcher.search(). On the first search query, this triggers loading of the ~2GB ColBERT neural reranking ONNX model, which takes >2 minutes before the first response is returned. This makes osgrep serve impractical for interactive use cases (e.g., Neovim pickers, editor integrations) where sub-second latency is expected.

Solution

Both serve and search commands now accept --no-rerank which passes { rerank: false } to searcher.search(). The searcher already handles this case gracefully (line 258 of searcher.ts: const doRerank = _search_options?.rerank ?? true) by falling back to fusion scoring.

For serve, the /search endpoint also reads rerank from the JSON request body, allowing per-request control. The CLI flag sets the server-wide default.

Performance

Benchmarked on a small project (~35 files):

Mode	First query	Warm queries
serve (default, rerank=true)	>120s	~60ms
serve --no-rerank	321ms	66ms
search --no-rerank (CLI)	~1.0s	~1.0s

The quality difference is minimal — fusion scoring (BM25 + vector similarity) produces good results; neural reranking adds marginal improvement primarily for ambiguous queries.

Usage

osgrep serve --no-rerank          # fast server startup, no reranking model loaded
osgrep search "auth" --no-rerank  # fast CLI search without reranking

# Per-request control via the HTTP API:
curl -X POST http://localhost:4444/search \
  -H 'Content-Type: application/json' \
  -d '{"query": "authentication", "limit": 10, "rerank": false}'

Changes

• src/commands/serve.ts: Add --no-rerank option, read rerank from request body with CLI default fallback
• src/commands/search.ts: Add --no-rerank option, pass to searcher.search(), forward to server when using HTTP client path

Summary by CodeRabbit

• New Features
  • Added --no-rerank CLI option to disable neural reranking
  • Reranking behavior is now configurable for both search and serve commands
  • HTTP server endpoints support per-request reranking overrides

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: daec859d-e583-4b5a-9ced-cf193ca0a2ec

📥 Commits

Reviewing files that changed from the base of the PR and between 9f2faf7 and ed816aa.

📒 Files selected for processing (2)

• src/commands/search.ts
• src/commands/serve.ts

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Walkthrough

Added --no-rerank CLI option to both search and serve commands, enabling neural reranking behavior control. The flag is threaded through request payloads and command execution paths, replacing previously hardcoded reranking defaults with configurable values.

Changes

Cohort / File(s)	Summary
Reranking Option Control src/commands/search.ts, src/commands/serve.ts	Introduces --no-rerank CLI option to both commands. Adds rerank boolean to parsed options and threads it through server requests and local search execution. Serve command implements per-request override logic where body.rerank takes precedence over CLI-derived defaults.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A rerank toggle hops into view,
Per request or command, we choose what's true,
No more hardcoded ways—now flexible and bright,
The neural engine dances left and right! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'feat: add --no-rerank flag to serve and search commands' directly and clearly summarizes the main change—adding a CLI flag to two commands to control neural reranking behavior.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Aetherall]

This PR was made with opencode, im using this patch in my shell quick navigation tool. in this scenario, i value the tradeoff of lesser quality result for startup speed. might be out of scope for the mcp usage, but its quite handy in the shell too !
If you want to i can redo this PR using my unassisted raw biological neurons ;)