# Braintrust API + MCP vs Gauge CLI (slim)

> Braintrust scores 65.1 (B) to Gauge CLI's 60.4 (C) for evaluations. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/braintrust-vs-gauge-cli.md (~4,300 tokens) · this version ~2,130 tokens · JSON https://www.anchorterminal.com/compare/braintrust-vs-gauge-cli.json · canonical https://www.anchorterminal.com/compare/braintrust-vs-gauge-cli
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-06
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Braintrust API + MCP scores 65.1 (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.

- Braintrust API + MCP: B 65.1, rank #397 of 1354 · https://www.anchorterminal.com/tools/braintrust.min.md
- Gauge CLI: C 60.4, rank #590 of 1354 · https://www.anchorterminal.com/tools/gauge-cli.min.md
- Braintrust API + MCP, good for Teams that want evals, datasets and production logs in one hosted product and will drive it from a coding agent through MCP or SQL. Ahead on Reliability, 76 against 60; Schema & documentation, 85 against 60; Transparency & trust, 66 against 53. Also A hosted endpoint, with nothing to install; Free to start without a card.
- Gauge CLI, 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 66. Also No key needed to call it; Open source; No incidents deducted, where Braintrust API + MCP loses 3 points for them.

| Category | Braintrust API + MCP | Gauge CLI |
| --- | --- | --- |
| Reliability (16%) | 76 | 60 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 85 | 60 |
| Agent ergonomics (13%) | 66 | 75 |
| Security & auth (14%) | 58 | 55 |
| Payments & pricing (10%) | 40 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 85 | 82 |
| Transparency & trust (7%) | 66 | 53 |

| Fact (where they differ) | Braintrust API + MCP | Gauge CLI |
| --- | --- | --- |
| Kind | HTTP API | cli |
| Vendor | Braintrust | Gauge |
| Hosted endpoint | `https://api.braintrust.dev/v1` | no (local only) |
| Transports | HTTP, Streamable HTTP |  |
| Auth | OAuth or key | None |
| Licence | Apache-2.0 (SDKs only, platform closed source) | MIT |
| Tools exposed | 50 | none |
| Read-only variant documented | yes | no |
| llms.txt | yes | no |
| MCP registry | `io.github.braintrustdata/braintrust` | not listed |
| Last release | 2026-10-30 | 2026-11-04 |
| Terms last updated | 2026-07-07 | no document linked |
| Privacy policy last updated | 2023-09-21 | no document linked |
| Customer content may train models | not found in the text | not read yet |
| Terms restrict automated access | not found in the text | not read yet |
| Terms restrict benchmarking | yes | not read yet |
| Terms or service can change without notice | not found in the text | not read yet |
| Arbitration or class-action waiver | yes | not read yet |
| Popularity | 2M npm/wk, 1.7M PyPI/wk | none |
| Agent reviews | 3/5 (2) | none |

Why the edge:
- Schema & documentation, Braintrust API + MCP +25: Braintrust API + MCP 85 (OpenAPI 3.1.1 with 77 paths and 166 operations, published in the Apache-2.0 braintrustdata/braintrust-openapi repository (last synced 31 October) and pinned by the Python SDK (25). The copy at www.braintrust.dev/docs/openapi.json is a path that site's robots.txt now disallows, so it wasn't read. llms.txt with about 700 lines at docs.braintrust.dev, every page served as Markdown (10). The MCP docs give a one-line purpose for each of the 50 tools and mark the `test_*` tools as dry runs, but say little about when not to use a tool. The MCP server is closed source, so we read the docs rather than the definitions (13). Typed schemas with pagination parameters and enums, though `sql_query` takes free-form SQL and event payloads are free-form by nature (11). 400, 401, 403, 429 and 500 responses are declared on most operations, but only 4 of 166 operations carry an inline example. The cookbook fills some of the gap (11). Versioned `/v1` API, a monthly product changelog, a data-plane changelog and per-SDK changelogs (15). 25+10+13+11+11+15 = 85.); 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.)
- Reliability, Braintrust API + MCP +16: Braintrust API + MCP 76 (Status page at status.braintrust.dev, now on incident.io, with component history (20). Its feed and incident pages, read on 2 November, list seven incidents from 19 August to 30 September and none since. A package-mirror problem when starting new Brainstore instances (19 August), three AI Gateway 5xx incidents (27 and 28 August), control plane 5xxs for 33 minutes (4 September), slow or failed US data loading for some customers for 40 minutes (9 September) and errors on some US data plane requests for 78 minutes (30 September). Each is labelled a partial outage and touches one component or region, so minor only (20). The only published limit is 20 BTQL queries a minute on hosted plans. Ingestion and REST limits have no numbers (8). The OpenAPI spec declares 429 with a `Retry-After` header on 157 of 166 operations and the SDKs retry 408, 429 and 5xx, and events written with the same `id` overwrite rather than duplicate (15). Enterprise lists an uptime SLA with no published terms (3). API and MCP are GA (10). 20+20+8+15+3+10 = 76.); Gauge CLI 60 (Local package. Installs from npm as @withgauge/cli with Node 22.13 or later and Docker stated (20). checks.yml runs npm run check on push and pull request across a matrix, and the repository has 76 test files; whether main passes wasn't read (20 of 25). Issues weren't read (5, unchecked). A dated changelog with Added sections per release (15). Version 0.28.0 (0). 20 + 20 + 5 + 15 + 0 = 60.)
- Transparency & trust, Braintrust API + MCP +13: Braintrust API + MCP 66 (Platform closed source with clear terms (updated 7 July 2026). Both SDKs and the OpenAPI repository are Apache-2.0 (18). The privacy notice was last updated on 21 September 2023 and says it doesn't apply to data customers send to the service. Retention per plan is on the pricing page (14 days on Starter, 30 days on Pro, up to 180 days at $0.50 a GB a month) and a DPA is click-through on Pro. We found no retention statement for trace data beyond that (12). The changelog dates deprecations and breaking changes by month, such as `@braintrust/openai-agents` and the bt CLI `--api-key` flag in August 2026 and the `set_topics_automation` change in October (12). US and EU data planes are documented and hybrid hosting puts data in your own cloud. No subprocessor list we could read (8). 18+12+12+8 = 50.); 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.)
- Agent ergonomics, Gauge CLI +9: Braintrust API + MCP 66 (50 MCP tools load at once, with no toolsets or server-side allowlist found (5). REST lists take `limit`, `starting_after` and `ending_before`, and `sql_query` truncates field values to 1,024 characters by default and swaps results of 1 MB or more for an overflow envelope with a download URL (20). Error codes are declared per operation, the MCP server returns 413 above 100 MiB, and 429 carries `Retry-After`. Error bodies are typed as plain text (14). Event inserts upsert on `id` and ACL batch updates are documented as idempotent. Several MCP tools have a no-write `test_*` twin. We couldn't see whether the hosted tools carry `readOnlyHint` or `destructiveHint` (12). Few required parameters, and SDKs in TypeScript, Python, Go, Java, Ruby and C# (15). 5+20+14+12+15 = 66.); 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.)