# Clear Thought 1.5 (slim)

> Clear Thought 1.5 is an open-source MCP server from Waldzell AI with one tool, clear_thought, that structures an agent's reasoning through 37 operations such as sequential thinking, mental models and decision frameworks. It runs locally over stdio from npm.

- Full: https://www.anchorterminal.com/tools/clear-thought.md (~6,050 tokens) · this version ~1,430 tokens · JSON https://www.anchorterminal.com/tools/clear-thought.json · canonical https://www.anchorterminal.com/tools/clear-thought
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

**F · 36.4/100 · rank #823 of 842 · #2 in Reasoning scaffolds · not agent-ready · confidence medium**


Assessment: One tool covers 37 reasoning operations with no credentials and no network calls in the published build. The npm package has had no release since 18 August 2025, six of seven open issues have no reply, and operation-specific input is an untyped `parameters` object.

## Facts

- Kind: MCP server · vendor: Waldzell AI · category: Reasoning scaffolds · legal entity: not named · provenance 13/100
- Local only (stdio): npm `@waldzellai/clear-thought-onepointfive`
- Auth: None · pricing: Free · x402: no · licence: MIT
- Probe metrics: not measured yet (probes haven't run)
- Tool: `clear_thought`, one tool. Required `operation` (enum of 37) and `prompt`. Optional `parameters` (free-form object), `context`, `sessionId` and `advanced`, of which the last three are not read by the 0.2.1 handler
- Operations: Sequential thinking with chain, tree, beam, MCTS and graph patterns, mental models, debugging approaches, decision frameworks, Socratic method, systems thinking, causal and statistical analysis, OODA loop, Ulysses protocol, four notebook operations and three session operations
- Resources: `guide://clear-thought-operations`, `guide://notebook-interaction`, nine `examples://` documents and a `notebook:///{name}` template. The example files are looked up relative to the working directory
- Runtime: Node.js 18 or later, from the npm package `@waldzellai/clear-thought-onepointfive` 0.2.1 (binary `clear-thought`). The repository also has an HTTP entry point built on the Smithery SDK, which the npm package does not ship
- State: In memory for the life of the process, with a limit of 100 thoughts a session. File persistence to `.ct-data` exists and is off by default
- Code execution: `notebook_run_cell` runs JavaScript in `node:vm`, 5 second default timeout, up to 200 executions a notebook. `code_execution` spawns Python with a 10 second timeout only when `allowCodeExecution` is set, which stdio does not expose
- Telemetry: None in the published 0.2.1. Main adds optional Shinzo instrumentation, off by default (`telemetryProvider` none) and inactive without a token
- Releases: 0.2.0 and 0.2.1 on npm, both 18 August 2025. No git tags and no changelog. The server reports version 0.0.5 in its MCP handshake
- Earlier package: `@waldzellai/clear-thought`, last published as 0.0.4 on 27 May 2025 from a separate repository, not marked deprecated on npm

- Scores: Reliability 28, Performance pending, Schema & documentation 39, Agent ergonomics 53, Security & auth 39, Payments & pricing 60, Task success pending, Maintenance & community 4, Transparency & trust 36 · negative events -2 · total over the 7 assessed categories
- Why: Reliability, Scored as local software, since the owner runs it over stdio. · Schema & documentation, One tool with a JSON Schema generated from zod, read from the source and the published build since we do not run vendor software. · Agent ergonomics, One tool with a 642-character description, about 160 tokens, and a small schema (25). · Security & auth, No credentials to hold or leak, so the middle band (20). · Payments & pricing, Free, self-hosted software with nothing to buy, so 20 + 20 + 20. No payment protocol (0). · Maintenance & community, The latest npm release, 0.2.1, is dated 18 August 2025, 417 days before this check (0). · Transparency & trust, MIT, an OSI licence, on npm and in the repository.
- Sources: 12, open questions: 6, both in the full twin
- Capabilities: reasoning.scaffold
- JSON: https://www.anchorterminal.com/api/v1/tools/clear-thought.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/clear-thought.svg` or a link to https://www.anchorterminal.com/tools/clear-thought from a page under github.com/waldzellai, or the README of github.com/waldzellai/clearthought-onepointfive, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Call `clear_thought` with `operation` and `prompt`. Put everything else in `parameters`, using the field names in the `guide://clear-thought-operations` resource
2. Do not call `mdp_planning` or `decision_networks`. The README shows them, and the tool's operation enum rejects both
3. Expect an extra `initialThought` object on 32 of the 37 operations, and each one uses a slot of the 100-thought session limit
4. Stop the server process yourself when the session ends. Open issues report that it does not exit when the client disconnects
5. Treat `notebook_run_cell` as unsandboxed code execution on the host, and do not pass it code from untrusted content

## Connect

```bash
npx @waldzellai/clear-thought-onepointfive
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/clear-thought

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Sequential Thinking (MCP reference server) | B | 62.5 | reasoning.scaffold | https://www.anchorterminal.com/tools/sequential-thinking-reference-server.min.md |


## Panel reviews (0, desk reviews from public material, no calls made)