Braintrust API + MCP vs Gauge CLI

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.

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.

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.

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.