localthink-mcp 2.1.0

Local Ollama-backed MCP server — 44 tools, smart buffer, execution filters, persistent scratchpad

localthink-mcp

Local LLM context compression for Claude Code. Offloads large file queries and document processing to Ollama so they never burn Claude's context window.

v0.1.0 benchmarked at ~30× token savings on 16 KB file queries. v1.1 adds 13 new tools covering every major token-waste pattern. v1.2 adds pre-injection: local_improve_prompt and local_preplan run locally before Claude sees the task — sharpening prompts and scaffolding plans so Claude executes rather than guesses. v2.1 adds smart buffer, execution filters, session scratchpad, persistent notes, response refinement, and a disk-backed result cache — 14 new tools, 44 total.

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Quick start

# 1. Pull a model (once)
ollama pull qwen2.5:14b-instruct-q4_K_M

# 2. Register with Claude Code
claude mcp add localthink -- uvx localthink-mcp

# 3. Verify
claude mcp list   # localthink → Connected

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Requirements

• Ollama installed and running (ollama serve)
• Claude Code CLI
• Python 3.10+

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All 44 tools

v0.1.0 — Core compression

Tool	When to use
local_answer(file_path, question)	Query a large file without loading it into context
local_summarize(text, focus?)	Compress a large text blob already in context
local_extract(text, query)	Pull only the cited passages you need from a document

v1.1 — New routes

File operations

Tool	What it does
local_shrink_file(file_path, focus?)	Read a file → return compressed content (not an answer). Hold the compressed version in context for repeated reference.
local_batch_answer(file_paths, question)	Answer one question across many files in a single call. No files enter Claude's context.
local_scan_dir(dir_path, pattern, question?, max_files?)	Walk a directory, summarize or query every matching file. Glob pattern support (**/*.ts, config/*.yaml).

Composition (fewer round-trips)

Tool	What it does
local_pipeline(text, steps)	Chain summarize → extract → answer in one call. Up to 5 steps. Eliminates back-and-forth for predictable multi-stage workflows.
local_auto(input, question?)	Meta-tool: detects file path vs text, picks the right op, handles large docs with auto extract-then-answer. Zero decision overhead.

Stateful document chat

Tool	What it does
local_chat(document, message, history?)	Multi-turn Q&A. Document is compressed on first call and stays with Ollama. Claude holds only conversation history — the original doc never enters Claude's window.

Semantic & structural

Tool	What it does
local_grep_semantic(file_path, meaning, max_results?)	Find passages matching a concept, not a literal string. "Find where rate limiting is enforced" works even if the word "rate" isn't there.
local_outline(text)	Structural table of contents with line ranges — no content returned. Use before local_extract to find the right section.
local_code_surface(file_path)	Public API skeleton. Python: pure AST (no Ollama, instant). Other languages: fast LLM. Typically 5-10% of original size.

Analysis / meta

Tool	What it does
local_classify(text)	Classify content type + recommend the best tool. Returns JSON. Use for programmatic routing in hooks/scripts.
local_audit(file_path, checklist)	Checklist-based file audit: PASS / FAIL / PARTIAL / N/A per item. File never enters Claude's context.
local_models()	List local Ollama models and show current DEFAULT / FAST model config.

v1.2 — Pre-injection (run before Claude thinks)

These tools run a local model pass before Claude engages with a task. Claude never sees the raw input — only the pre-processed output. Eliminates waste at the source rather than compressing after the fact.

Tool	What it does
local_improve_prompt(prompt, context?)	Rewrite a vague or rough prompt into a clear, specific, unambiguous version. Claude receives only the sharpened result. Uses the fast model — minimal overhead.
local_preplan(task, context?, depth?)	Generate a structured implementation plan (goal / assumptions / ordered steps / risks / open questions) via local model. Claude executes the scaffold rather than planning from scratch. depth: "quick" (3-5 steps), "standard" (default), "detailed" (sub-bullets + rationale).

local_improve_prompt example:

"make the auth faster"
→ local_improve_prompt(prompt, context="Next.js, JWT, DB bottleneck suspected")
→ "Optimise JWT validation latency in src/auth/middleware.ts — profile the verify()
   hot path, remove redundant DB round-trips, target p95 < 5 ms."
→ Feed that to Claude as the actual task

local_preplan example:

plan = local_preplan(
  task="add rate limiting to the API",
  context="Express.js, Redis available, routes in src/routes/",
  depth="standard"
)
# Returns: Goal / Assumptions / Steps with file paths / Risks / Open questions
# Then: "Execute this plan: <plan>"

v1.1 expansion — high-context compression + smart reading

High-context compression

Tool	What it does
local_compress_log(file_path, level?, since?)	Compress a log file to its essential signal. Groups repeated errors with counts, extracts key events, surfaces anomalies. Optional level (ERROR/WARN) and timestamp-prefix filters. Turns 5 MB logs into ~500-token summaries.
local_compress_stack_trace(text)	Distil a stack trace (+ source context) to: root cause, failure point, 3-5 key frames, fix hint. Eliminates framework boilerplate that inflates traces to thousands of tokens.
local_compress_data(data, keep_fields?, question?)	Compress JSON objects, CSV exports, and API responses. Strips nulls, samples large arrays, keeps IDs/status codes. REST responses commonly shrink 20:1.
local_session_compress(file_path)	Recursive meta-tool. Compress a saved Claude conversation transcript to a re-entry briefing: context, decisions, current state, open items, constraints. The transcript never enters Claude's context.
local_prompt_compress(text)	Compress a long CLAUDE.md or system prompt to its minimal directive set. Preserves every unique rule; removes duplicates and verbose prose.

Smart reading (avoid loading files at all)

Tool	What it does
local_symbols(file_path)	Full symbol table: every definition with type, line number, and one-line description. Replaces "read file to see what's in it."
local_find_impl(file_path, spec)	Natural-language code search inside a file. Returns the complete matching logical unit with line numbers. E.g. spec="where JWT token is verified".
local_strip_to_skeleton(file_path)	All function bodies → ..., everything else preserved (docstrings, decorators, type annotations, comments). Typically 30-50% of original.

Format transformation

Tool	What it does
local_translate(text, target_format)	Convert formats without loading source into context: json↔yaml↔toml, csv→markdown_table, code→pseudocode, sql→english, env→json.
local_schema_infer(data)	Sample data → compact JSON Schema (draft-07). API samples are often 100:1 data-to-schema ratio.

Temporal & multi-file diff

Tool	What it does
local_timeline(text)	Chronological event sequence from logs, changelogs, git log, or incident reports. Deduplicates repeated events.
local_diff_files(path_a, path_b, focus?)	Diff two files by path — neither file loaded into context. Counterpart to local_diff which takes in-context text.

v2.1 — Smart buffer, execution filters, scratchpad, notes, cache

Smart Buffer (raw output triage)

Tool	What it does
local_gate(raw_output)	Triage any raw output (test results, build logs, lint dumps) into Pattern + Anomalies + Signal. Always fits in budget. Use before injecting any raw tool output into context.
local_slice(file_path, offset_lines)	Read a window of lines from a file at an offset. On-demand raw access when local_gate identifies a region worth inspecting.
local_diff_semantic(before, after)	Meaning-level diff — noise (whitespace, formatting, minor rewording) suppressed. Only semantic changes surface.

Execution Filters (project tools → local LLM)

Tool	What it does
local_run_tests()	Run the project test suite. Returns only {failed, delta, pointer}. Nothing else enters context.
local_run_lint()	Run the linter. Violations grouped by rule; passing rules suppressed.
local_run_build()	Run the build. Returns root cause + affected symbols only.

Session Scratchpad (stateful decisions)

Tool	What it does
local_memo_write(section, content)	Write to a named scratchpad section: decisions, assumptions, pitfalls, open_questions. Auto-compacts beyond threshold.
local_memo_read()	Read the full scratchpad as a distilled summary. Restore context mid-session without re-reading files.
local_memo_checkpoint()	Freeze scratchpad into a RESUME_PROMPT string. Paste after /clear to continue with full context.

Persistent Notes (cross-session knowledge)

Tool	What it does
local_note_write(category, content)	Write a permanent note to disk (architecture, gotcha, pattern). Survives /clear and new sessions.
local_note_search(query)	Full-text search across all persisted notes. Run at session start to surface relevant prior knowledge.

Response Quality & Cache

Tool	What it does
local_refine(prompt, draft, instructions?)	Post-process an LLM draft through a refinement pass. Optional instructions target tone, brevity, or accuracy.
local_cache_stats()	Show cache hit/miss counts, entry count, and total disk usage.
local_cache_clear()	Evict all cached results.

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Decision guide

Situation	Tool
File > 5 KB, one specific question	local_answer
File > 5 KB, need to reference it multiple times	local_shrink_file
Text already in context, want to compress it	local_summarize
"Find me the part about X"	local_extract
Need to outline a doc before extracting	local_outline → local_extract
Want to know what's in a code file	local_symbols
Want to understand a code file's structure	local_code_surface
Want the full file but bodies stripped	local_strip_to_skeleton
"Find the function that does X"	local_find_impl
Multi-step process on the same document	local_pipeline
Unsure which tool to use	local_auto
Multiple questions about the same large doc	local_chat
Same question across 5+ files	local_batch_answer
Understand what's in a directory	local_scan_dir
"Find where X is handled" (concept search)	local_grep_semantic
Security or quality checklist	local_audit
Unsure of content type before processing	local_classify
Large log file	local_compress_log
Stack trace + source context	local_compress_stack_trace
JSON / CSV / API response payload	local_compress_data
Session too long, need to restart	local_session_compress
CLAUDE.md grown too large	local_prompt_compress
Need JSON as YAML (or any format swap)	local_translate
Need a schema for sample data	local_schema_infer
Need a timeline from a log or changelog	local_timeline
Compare two files without loading them	local_diff_files
Compare two in-context text blobs	local_diff
Prompt is vague — sharpen before sending to Claude	local_improve_prompt
Task is large — plan locally before Claude touches it	local_preplan
Raw test/build/lint output about to enter context	local_gate
local_gate flagged a specific region worth reading	local_slice
Two text blobs — want only the meaningful diff	local_diff_semantic
Run tests without dumping output into context	local_run_tests
Run lint without dumping output into context	local_run_lint
Run build without dumping output into context	local_run_build
Want to record a decision or assumption mid-session	local_memo_write
Resuming work, need to restore session context	local_memo_read
About to /clear — want to resume with full context	local_memo_checkpoint
Want to save a pattern or gotcha for future sessions	local_note_write
Starting a session — check for relevant prior notes	local_note_search
LLM draft needs a quality pass	local_refine
Check or clear the result cache	local_cache_stats / local_cache_clear

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local_pipeline examples

# Extract auth sections, then summarize for security review
local_pipeline(text=big_doc, steps=[
    {"op": "extract",   "query": "authentication and authorization"},
    {"op": "summarize", "focus": "security risks and gotchas"},
])

# Answer a question after narrowing to the relevant section
local_pipeline(text=api_docs, steps=[
    {"op": "extract",  "query": "rate limiting"},
    {"op": "answer",   "question": "what headers control retry behaviour?"},
])

local_chat example

# Turn 1 — document is compressed automatically
r = local_chat(full_doc, "What does this library do?", "")
# r["doc"]     = compressed version (hold this)
# r["history"] = conversation so far (hold this)
# r["answer"]  = the answer

# Turn 2 — pass compressed doc + history back
r = local_chat(r["doc"], "How do I configure auth?", r["history"])

# Turn 3
r = local_chat(r["doc"], "Show me the relevant config keys", r["history"])

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Configuration

Env var	Default	Description
OLLAMA_BASE_URL	http://localhost:11434	Ollama endpoint
OLLAMA_MODEL	qwen2.5:14b-instruct-q4_K_M	Model for all quality operations
OLLAMA_FAST_MODEL	(same as OLLAMA_MODEL)	Lighter model for classify, outline, code_surface on non-Python
LOCALTHINK_CACHE_DIR	OS temp dir	Directory for disk-backed result cache
CACHE_TTL_DAYS	7	Cache entry time-to-live in days

Smaller fast model example (qwen2.5:3b for lightweight ops):

{
  "mcpServers": {
    "localthink": {
      "env": {
        "OLLAMA_MODEL":       "qwen2.5:14b-instruct-q4_K_M",
        "OLLAMA_FAST_MODEL":  "qwen2.5:3b-instruct"
      }
    }
  }
}

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Install options

uvx (recommended — zero setup)

claude mcp add localthink -- uvx localthink-mcp

pip

pip install localthink-mcp
claude mcp add localthink -- localthink-mcp

Windows — if uvx isn't on Claude's PATH

claude mcp add --transport stdio localthink -- cmd /c uvx localthink-mcp

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Security

• Local only — runs as a stdio child process, never exposed to the network.
• local_answer / local_shrink_file / local_audit read any path your shell can access. Same trust level as Claude's built-in Read tool.
• Ollama has no auth by default. Don't expose port 11434 to the internet.
• No data leaves your machine. All inference is local.

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Troubleshooting

[localthink] Ollama is not running

ollama serve
curl http://localhost:11434/api/tags

Slow responses Switch to a smaller model or set a fast model:

OLLAMA_MODEL=qwen2.5:7b-instruct claude

Windows: uvx not found Install uv, then retry. Or use cmd /c uvx fallback.

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License

MIT © 2026 H3xabah