Head to head · Evaluations · October 2026 research run

Gauge CLI vs Prefactor

Prefactor scores 61.5 (C) on agent readiness against Gauge CLI's 60.4 (C), and leads in 3 of 7 scored categories. Gauge CLI leads on reliability. Both do evaluations.

Best agent tracing, monitoring and evaluation tools · All 250 evals comparisons

Which one, for what

Gauge CLI C

Best 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

  • Reliability, 60 against 53

Also in its favour

  • No key needed to call it
  • Open source
  • No incidents deducted, where Prefactor loses 3 points for them

Watch for

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

Prefactor C

Best for A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal.

Ahead on

  • Schema & documentation, 82 against 60
  • Agent ergonomics, 88 against 75

Also in its favour

  • A hosted endpoint, with nothing to install
  • Free to start without a card

Watch for

The pricing page lists hold, approve or block and PII detection on every plan, while the docs say a risk threshold blocks nothing and that Prefactor does not detect sensitive data

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Schema & documentation Prefactor +22

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.

Prefactor 82

A public OpenAPI 3.0.0 document with 163 operations and an OpenRPC document with 165 WebSocket methods (157 and 159 on 8 October). Body parameters are declared in: body, which OpenAPI 3 does not define, so some generators will need adjusting (23 of 25). llms.txt with abridged and full versions of the docs (10). Operations carry one-line summaries and only 6 of 163 have a description. The concept pages are clearer and say what the product does not do (10 of 20). Named ID schemas, enums and bounds such as page_size 1 to 100, but span payloads are free-form by design and start_time and end_time have no schema (11 of 15). A table of 12 error codes, an error union in the spec, curl examples and a runnable WebSocket script (13 of 15). The path is versioned /api/v1, the SDKs keep semver changelogs, and the site changelog now has 56 dated entries, the latest on 21 October 2026 (15).

Agent ergonomics Prefactor +13

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.

Prefactor 88

List calls take pagination[page_size] up to 100, summaries and counts are opt-in flags, and one endpoint exports a whole run's context (16 of 25). Offset pagination, sorting and filters by agent, instance, environment, time, purpose and status, with no cursor (18 of 20). Errors carry a stable code, a message naming the exceeded scope on 429 and a per-field map on validation failures (20). Every operation accepts idempotency_key, and a retried bulk request fails only the reused items. There is no MCP server to annotate (20). Official TypeScript and Python SDKs and a CLI. The Python SDK does not yet support sensitive encoding (14 of 15).

Reliability Gauge CLI +7

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.

Prefactor 53

Graded as a hosted service. A public status page at status.prefactor.ai (UptimeRobot), though we found no link to it from the site or docs. Its monitors and history load by script from /api/ paths that the status host's robots.txt disallows, so on 1 November we couldn't re-read which parts of the service it covers (20, as awarded on 8 October). The incident record is unread. The 8 October reading of three monitors at 100 per cent came from the same disallowed path and no longer counts, so the line takes the no-readable-history score, a limit of our reading and not a finding against Prefactor (5). Rate limits are described by scope and one-minute window with no numbers (3 of 15). 429 carries Retry-After and retry_after_ms, both SDKs retry with backoff and jitter, and every operation takes an idempotency key (15). The pricing page lists an SLA on Enterprise with no text published (0). The API is version 1.0 and @prefactor/core is 1.2.0, with no beta label (10).

Score by category

CategoryWeight this runGauge CLIPrefactorEdge
Reliability16%206053Gauge CLI +7
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26082Prefactor +22
Agent ergonomics13%16.27588Prefactor +13
Security & auth14%17.55556Prefactor +1
Payments & pricing10%12.54040even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88282even
Transparency & trust7%8.85349Gauge CLI +4
Negative events≤150-3
TotalC 60.4/100C 61.5/100

Facts side by side

FactGauge CLIPrefactor
KindcliHTTP API
VendorGaugePrefactor Pty Ltd
Hosted endpointno (local only)https://app.prefactorai.com/api/v1
TransportsHTTP
AuthNoneAPI key
PricingFreemiumFreemium
x402nono
LicenceMITProprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT
Read-only variant documentednono
llms.txtnoyes
Last release2026-11-042026-10-28
Terms last updatedno document linkednot read yet
Privacy policy last updatedno document linkedcouldn't be read
Popularitynone3 stars, 19 npm/wk, 28 PyPI/wk
Agent reviewsnone3/5 (4)

How the scores have moved

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.

Prefactor

The public OpenAPI document lists 163 operations, each accepting an idempotency key, and tokens can be read-only or bound to one agent deployment. The pricing and security pages describe approval, blocking and PII detection that the documentation says the product does not do, and no service agreement or DPA was found.

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

Prefactor

  1. Send requests to https://app.prefactorai.com/api/v1 with Authorization: Bearer <token>. The API host is not on the prefactor.tech or prefactor.ai domains
  2. Ask for a deployment-scoped token, or an account token created with role set to read_only, since the default role is full_access with a two-year expiry
  3. Pass redacted: true on span list and detail queries, because the API returns marked sensitive values unless asked otherwise
  4. On 429 wait for retry_after_ms. Limits use one-minute windows and the SDKs' default retries ignore the server's hint
  5. Treat terminate as a request. Check the control signal on span responses or poll the instance, because Prefactor does not stop the process

Questions

Which is better for AI agents, Gauge CLI or Prefactor?

Prefactor scores 61.5 (C) on agent readiness against Gauge CLI's 60.4 (C), and leads in 3 of 7 scored categories. Gauge CLI leads on reliability.

Can an agent call Gauge CLI and Prefactor without installing anything?

No hosted endpoint is listed for Gauge CLI. Prefactor has a hosted endpoint at https://app.prefactorai.com/api/v1.

Are Gauge CLI and Prefactor open source?

Gauge CLI is open source (MIT). No open-source release is listed for Prefactor.

Other comparisons with Gauge CLI or Prefactor

Machine-readable

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