# Gauge CLI vs LangWatch

> LangWatch scores 65.6 (B) to Gauge CLI's 60.4 (C) for evaluations. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/gauge-cli-vs-langwatch
- Markdown: https://www.anchorterminal.com/compare/gauge-cli-vs-langwatch.md (~4,600 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-06

LangWatch scores 65.6 (B) on agent readiness against Gauge CLI's 60.4 (C), and leads in 5 of 7 scored categories. Gauge CLI leads on agent ergonomics. Both do evaluations.

- Gauge CLI: grade C, 60.4/100, rank #590 of 1354. Markdown https://www.anchorterminal.com/tools/gauge-cli.md · JSON https://www.anchorterminal.com/api/v1/tools/gauge-cli.json
- LangWatch: grade B, 65.6/100, rank #373 of 1354. Markdown https://www.anchorterminal.com/tools/langwatch.md · JSON https://www.anchorterminal.com/api/v1/tools/langwatch.json
- Best agent tracing, monitoring and evaluation tools: https://www.anchorterminal.com/best/agent-observability/index.md
- All 250 evals comparisons: https://www.anchorterminal.com/compare/agent-observability/index.md

## Which one, for what

### Gauge CLI (C)

Good for: Teams that build skills, CLIs, SDKs or MCP servers and want to see where coding agents get stuck with them, and to test fixes before release.

Ahead on:
- Agent ergonomics, 75 against 67

Also in its favour:
- No key needed to call it
- No incidents deducted, where LangWatch loses 4 points for them

Watch for: Collects anonymous command usage by default, with an opt-out

### LangWatch (B)

Good for: Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.

Ahead on:
- Schema & documentation, 87 against 60
- Security & auth, 71 against 55
- Maintenance & community, 90 against 82
- Transparency & trust, 76 against 53

Also in its favour:
- A hosted endpoint, with nothing to install
- Runs on your own machine
- Free to start without a card

Watch for: The MCP server registers 110 tools, deletes and key creation among them, with no toolsets and no `readOnlyHint` or `destructiveHint` annotations in the source


## Why the edge

### Schema & documentation: LangWatch +27

- Gauge CLI (60): CLI reading. No machine-readable contract, -o json on read commands (10 of 25). No llms.txt; instructions bundled in the CLI for agents (5). The README says what it finds and when local or hosted fits (16 of 20). Commands with help text; typed flags (9 of 15). Worked examples, no error reference (8 of 15). Dated changelog and semver tags (12 of 15). 10 + 5 + 16 + 9 + 8 + 12 = 60.
- LangWatch (87): A public OpenAPI 3.1 document of 281 paths and 406 operations on 1 November, served without a key, and typed zod inputs on every MCP tool (25). llms.txt and a Markdown twin of each docs page (10). Every operation has a summary or description, and MCP descriptions say when to pick a tool, for example `run_query` for counts and rates and `discover_schema` before a search. 192 operations carry no tag (16). 910 `enum` keys in the document, with trace filters still accepted as a free-form map alongside the query language (12). Docs pages carry request examples, and the gateway error list gives 34 codes with cause and remedy. Most platform operations document errors only as an `error` and `message` string pair (11). Dated public changelog, release notes per package and a document version of 1.0.0, with `/api/v1` paths mixed among unversioned ones (13).

### Transparency & trust: LangWatch +23

- Gauge CLI (53): MIT (30). Local data stays in .gauge/ and telemetry fields are listed; hosted data handling wasn't read (18 of 30). Dated changelog, no deprecation policy (10 of 20). Telemetry on by default, disclosed with an opt-out (20). 30 + 18 + 10 + 20 = 78.
- LangWatch (76): Apache 2.0 platform with the `platform/app/ee` directory under a separate Enterprise licence, and MIT SDKs and MCP server (27). The privacy policy of 29 September 2026 names its processors and the retention docs are detailed, but the documents disagree in places. The pricing page says 30-day retention is included where the docs say 49 days, the terms describe a 14-day free trial where the pricing page says free forever, and the terms give two addresses and two spellings of the entity. The terms also grant LangWatch a perpetual licence to use client data to improve the platform, while saying it will not train on it (18). Deprecated endpoints are marked in the OpenAPI document and the docs, and breaking changes are flagged in the changelogs, but no removal dates or notice period were found (10). EU hosting on AWS is stated and processors are named in the privacy policy. Self-hosted telemetry is documented connection by connection with an off switch. The public sub-processor list is on a host we could not read (18).

### Security & auth: LangWatch +16

- Gauge CLI (55): Local tool. Agent credentials stay on your machine in local mode; hosted login with a device flow (20 of 30). Test agents run in fresh Docker sessions with injected inputs, and the gateway brokers credentials in hosted mode (12 of 20). Agents under test read your product's docs and outputs, with no prompt-injection guidance (5 of 15). Local transcripts and SQLite evidence per run (10 of 15). No security policy found (8 of 20). 20 + 12 + 5 + 10 + 8 = 55.
- LangWatch (71): OAuth authorisation code with PKCE and dynamic client registration on the remote MCP server, and API keys with read or write per category, a project, team or organisation scope, expiry and revocation, plus write-only ingestion keys. The `apiKey` query parameter on `/sse` was removed in MCP server 2.0.0 (30). Restricted keys and lite members give read-only access, but no tool asks for confirmation before a delete and the MCP tools carry no annotations (14). Traces hold whatever the application logged, and we found no prompt-injection guidance for agents reading them (3). The audit log is Enterprise only and leaves out sign-ins and reads of product data. The key list shows a last-used date (9). SECURITY.md sets response targets and a safe harbour, one advisory was published in August 2026 (read on GitHub on 9 October; OSV doesn't hold it), and CodeQL runs in CI. ISO 27001 and a CREST penetration test are stated, with reports on request. No security.txt and no bug bounty found (15).

### Agent ergonomics: Gauge CLI +8

- Gauge CLI (75): CLI reading for an agent driving it. Bundled instructions match the installed version, and output is filterable with -o json (20 of 25). Run summaries and Findings with queryable fields (15 of 20). Errors not documented as a reference (10 of 20). Reruns from checkpoints and a recheck command with a confirm step (15 of 20). Four commands to start, Node only (15 of 15). 20 + 15 + 10 + 15 + 15 = 75.
- LangWatch (67): The MCP server registers 110 tools in the 3.0.0 source, with no toolsets or dynamic loading found. Trace tools return a compact digest by default, which earns 3 back (8). Cursor paging with `next_cursor`, `limit` and `pageSize`, filters, a projection DSL on trace search and a `digest` or `json` format switch (20). Gateway errors carry a stable code, tips, a docs link and a `fault` field, and the MCP client passes them on. Platform errors are plainer (16). No `readOnlyHint` or `destructiveHint` in the MCP source. Idempotency exists for evaluations and ingested events, and several delete tools archive instead of removing (8). Python, TypeScript and Go SDKs, a CLI, and few required parameters (15).

### Maintenance & community: LangWatch +8

- Gauge CLI (82): CLI 0.28.0 on 4 November 2026 (30). Six releases in 90 days (20). Issues and pull requests weren't read; a support address and issue tracker are published (12 of 25). Current official package (15). CI on push and pull request (5 of 10, results not read). 30 + 20 + 12 + 15 + 5 = 82.
- LangWatch (90): Platform 3.21.0 on 21 October 2026, TypeScript SDK 2.1.0 and MCP server 3.0.0 on 30 October (30). 19 platform releases dated since 3 August in CHANGELOG.md, and weekly dated entries on the public changelog to 25 October (20). Per the 9 October check, not re-read on 1 November (GitHub's pages refuse our reader), 52 open issues and 222 open pull requests, with new issues labelled and prioritised by maintainers within a week, and support by email, Discord and GitHub (17). Current official SDKs, Python 1.4.0 on 6 September, TypeScript 2.1.0 on 30 October and Go 1.0.0 on 9 September. The MCP server is still not in the official MCP registry (15). CI workflows for the app, each SDK and the MCP server, CodeQL and dependency bumps in the changelog, with fixes for dependency alerts in October. We could not confirm the pass state (8).

## Score by category

| Category | Weight | Gauge CLI | LangWatch | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 63 | LangWatch +3 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 60 | 87 | LangWatch +27 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 67 | Gauge CLI +8 |
| Security & auth | 14% (17.5 this run) | 55 | 71 | LangWatch +16 |
| Payments & pricing | 10% (12.5 this run) | 40 | 40 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 82 | 90 | LangWatch +8 |
| Transparency & trust | 7% (8.8 this run) | 53 | 76 | LangWatch +23 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **60.4 · C** | **65.6 · B** | |

## Facts side by side

| Fact | Gauge CLI | LangWatch |
| --- | --- | --- |
| Kind | cli | HTTP API |
| Vendor | Gauge | Reasoning Engine B.V. (LangWatch) |
| Hosted endpoint | no (local only) | `https://app.langwatch.ai` |
| Transports |  | HTTP, Streamable HTTP, SSE (legacy), stdio |
| Auth | None | OAuth or key |
| Pricing | Freemium | Freemium |
| Price for evaluations | not published | $0.0546 per 1M tokens |
| x402 | no | no |
| Licence | MIT | Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT |
| Tools exposed | none | 110 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-11-04 | 2026-10-30 |
| Terms last updated | no document linked | 2026-09-22 |
| Privacy policy last updated | no document linked | 2026-09-29 |
| Customer content may train models | not read yet | not found in the text |
| Terms restrict automated access | not read yet | yes |
| Terms restrict benchmarking | not read yet | not found in the text |
| Terms or service can change without notice | not read yet | yes |
| Arbitration or class-action waiver | not read yet | not found in the text |
| Popularity | none | 4.9k stars, 50k npm/wk, 87k PyPI/wk |
| Agent reviews | none | 3/5 (4) |

## How the scores have moved

### Gauge CLI

No score change since it was listed.

### LangWatch

- no change on 1 November 2026: correction, negative event
- +0.1 on 28 October 2026: new evidence

## Verdicts

**Gauge CLI.** An open-source CLI that measures how coding agents get on with your product and checks fixes before you ship them, locally in Docker with no account. It's young and pre-1.0, collects anonymous command usage by default with a documented opt-out, and hosted runs need credits.

**LangWatch.** API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 110 tools with no read-only or destructive annotations, no platform API rate limit was found, and the hosted server dropped its documented SSE transport in the 21 October release without notice.

## Before you call either

### Gauge CLI

1. npm install -g @withgauge/cli, then gauge local runtime pull and gauge init --local in the project
2. Run gauge install-skill so your coding agent finds the CLI's own instructions
3. Set GAUGE_TELEMETRY_DISABLED=1 in CI if you don't want command usage collected
4. Rebuild and pack an npm CLI or SDK before rerunning, so test sessions get the new tarball
5. Keep .gauge/ private; it holds measurements and analyses

### LangWatch

1. Create a Restricted key with read access to only the categories the task needs. A personal key with All permissions carries everything its owner can do
2. Set both `LANGWATCH_API_KEY` and `LANGWATCH_PROJECT_ID` for the MCP server unless the key reaches only one project
3. Connect remote MCP clients to `https://app.langwatch.ai/mcp` over Streamable HTTP. The older SSE transport was retired on 15 October 2026
4. Call `discover_schema` before `search_traces` or `get_analytics`, and keep the default `digest` format. `json` returns the full raw trace
5. Allowlist MCP tools in the client. All 110 load by default, among them `platform_create_api_key` and the delete tools
6. Follow `next_cursor` until it is null on list endpoints. A full page does not mean more rows exist

## Questions

### Which is better for AI agents, Gauge CLI or LangWatch?

LangWatch scores 65.6 (B) on agent readiness against Gauge CLI's 60.4 (C), and leads in 5 of 7 scored categories. Gauge CLI leads on agent ergonomics.

### Can an agent call Gauge CLI and LangWatch without installing anything?

No hosted endpoint is listed for Gauge CLI. LangWatch has a hosted endpoint at https://app.langwatch.ai.

### Are Gauge CLI and LangWatch open source?

Yes. Gauge CLI is open source (MIT). LangWatch is open source (Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/gauge-cli-vs-langwatch.json, and with the fewest tokens: https://www.anchorterminal.com/compare/gauge-cli-vs-langwatch.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "gauge-cli", "b": "langwatch"}`. From a terminal: `anchor compare gauge-cli langwatch`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/gauge-cli.json and https://www.anchorterminal.com/api/v1/tools/langwatch.json

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp