Head to head · Agent harnesses · October 2026 research run

Jules vs T3 Code

T3 Code scores 51.9 (D) on agent readiness against Jules's 45.1 (E), and leads in 3 of 7 scored categories. Jules leads on schema & documentation and security & auth. Both do agent harnesses.

Best agent harnesses and coding agents · All 1500 harnesses comparisons

Which one, for what

Jules E

Best for Nobody starting new work, since Jules turns read-only after 11 November 2026 and ends on 31 December 2026.

Ahead on

  • Schema & documentation, 76 against 55
  • Security & auth, 57 against 35

Also in its favour

  • Runs on your own machine

Watch for

Jules turns read-only after 11 November 2026 and winds down on 31 December 2026, per the changelog of 29 October

T3 Code D

Best for Developers who want one app, including on their phone, to drive several coding agents they already pay for.

Ahead on

  • Reliability, 43 against 13
  • Payments & pricing, 60 against 30
  • Maintenance & community, 75 against 18

Also in its favour

  • No key needed to call it
  • Open source

Watch for

Usage data on by default, with hashed OpenAI and Claude account identifiers, and relay traces to Axiom

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.

Maintenance & community T3 Code +57

Jules 18

Closed service. The newest API or product change is the changelog entry of 9 March 2026, 241 days before 5 November (0). The changelog's 29 October 2026 entry announces the wind-down and an export route through the CLI, which is a notice, not an API change. No package releases, commits or tags in the 90 days, and the jules-sdk repository's last commit is 18 March 2026 (0). A public changelog and a Discord channel. The 18 October issue and pull request counts came from shields.io badges and are struck (8 of 15, a partial held). The official TypeScript SDK and MCP packages last published 0.2.0 on 9 March 2026, per the 18 October registry reading, and no official MCP registry entry could be read (5). The SDK has a CI workflow on pull requests whose results couldn't be read, and two runtime dependencies. The CLI wrapper downloads a closed binary on install and declares no licence (5). 0 + 0 + 8 + 5 + 5 = 18.

T3 Code 75

Commits and nightly tags on 6 November 2026 (30). More than three releases in 90 days (20). GitHub issues and pull requests weren't read (GitHub's pages refuse these sessions), so that line is scored absent (0). Current official apps and install script (15). CI on push (10). 30 + 20 + 0 + 15 + 10 = 75.

Reliability T3 Code +30

Jules 13

Hosted reading. No status page for Jules was found (0). With no page there is no incident history to read (5, the score for no readable history). The plans page, re-read on 5 November, publishes task quotas with numbers, 15, 100 and 300 tasks a rolling 24 hours and 3, 15 and 60 concurrent, and list pageSize is capped at 100, but no request rate figures were found (8 of 15). 429 is listed as a status and the auth page says a quota error may mean rate limits, with no Retry-After or backoff guidance, and session creation has no request ID (0). No SLA found (0). The API is v1alpha and labelled experimental, and the changelog of 29 October 2026 says Jules turns read-only after 11 November (0). 0 + 5 + 8 + 0 + 0 + 0 = 13.

T3 Code 43

Local software. An install script and desktop and mobile apps from the vendor (20). ci.yml and windows-tests.yml run on the repository; pass state not read (15). GitHub issues and pull requests weren't read (GitHub's pages refuse these sessions), so that line is scored absent (0). Stable tags v0.1.5 to v0.1.7 with many nightlies, no changelog file (8). Version 0.1.7 (0). 20 + 15 + 0 + 8 + 0 = 43.

Payments & pricing T3 Code +30

Jules 30

Published rubric. No payment protocol (0). Plans and their Jules limits are public without a login, and Jules sits inside the Google AI plans. The prices render per locale and weren't read, and there's no per-task price (10). A free plan of 15 tasks a day with a Google account, and no card step in the sign-up docs, until new tasks stop after 11 November 2026 (20). A person signs in, accepts the privacy notice, installs the GitHub app and creates the key in the web app (0). 0 + 10 + 20 + 0 = 30.

T3 Code 60

Free self-hosted software with nothing to buy, so 0 for a protocol and 20 each for public pricing, a free tier and onboarding with no sign-up, 60.

Security & auth Jules +22

Jules 57

Hosted reading. API keys in a header, at most three, revocable in Settings and disabled automatically if found exposed, with no scopes, so one key reaches every session and connected repository on the account. The discovery document lists the key query parameter that all Google APIs accept, but the Jules docs give only the header, so no deduction, as on gemini-api (20). Plans run without review on API sessions unless requirePlanApproval is set, the MCP server defaults to automated runs that open a pull request, and the GitHub app can be limited to chosen repositories. No read-only key (10). Each VM has internet access and the FAQ puts the burden on the user. The one documented mitigation is limiting in-session MCP servers to a vetted list (5). Activities log every plan, message, bash command and patch per session. No account audit log of key use found (8). www.google.com security.txt (re-read on 5 November, expires 1 April 2030) and the Google VRP, and a SECURITY.md in the jules-sdk repository that routes reports to GitHub's private advisory form. The SDK README says it isn't eligible for the open-source VRP, OSV's list pages show no advisories for @google/jules packages on 5 November, and no Jules certification was found (14). 20 + 10 + 5 + 8 + 14 = 57.

T3 Code 35

Harness reading. Product usage events go by default to ingest.t3.codes and PostHog, with hashed identifiers for your T3 Connect, OpenAI and Claude accounts, and relay traces to Axiom, which can include machine names and error text. Off with T3CODE_TELEMETRY_ENABLED=false or a managed policy. Disclosed in docs/user/telemetry.md, not the README (10 of 30). Permission modes and managed policies (12 of 20). No prompt-injection guidance (5). No audit log (5). No security policy file found (3). 10 + 12 + 5 + 5 + 3 = 35.

Schema & documentation Jules +21

Jules 76

API reading. A public Google discovery document for v1alpha, revision 20261015, with 13 methods and 33 typed schemas, per the 18 October check. It sits on the API's own host and wasn't requested again (25). docs/llms.txt and a Markdown twin of every docs page (10). Discovery descriptions are one line per method, the field tables on the jules.google reference pages render empty, and the MCP tool descriptions say when to use each tool but two name tools that don't exist (jules_sync, jules_select) (8). Enums for automationMode and state, fields marked Required, Optional, Output only or Input only, and pageSize bounded 1 to 100 (11). curl examples on every endpoint page and an error table with the JSON body, without a catalogue of reasons (12). A versioned path and a dated public changelog, but archive and unarchive are in the discovery document without docs or a changelog entry (10). 25 + 10 + 8 + 11 + 12 + 10 = 76.

T3 Code 55

Harness reading. User docs in the repository (managed policy, handoffs, providers, telemetry), AGENTS.md for contributors, a server other clients connect to (55).

Score by category

CategoryWeight this runJulesT3 CodeEdge
Reliability16%201343T3 Code +30
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27655Jules +21
Agent ergonomics13%16.26460Jules +4
Security & auth14%17.55735Jules +22
Payments & pricing10%12.53060T3 Code +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81875T3 Code +57
Transparency & trust7%8.85151even
Negative events≤1500
TotalE 45.1/100D 51.9/100

Facts side by side

FactJulesT3 Code
KindAgent harnessAgent harness
VendorGoogle LLCT3 Tools Inc.
Hosted endpointno (local only)no (local only)
TransportsHTTP, stdio
AuthOAuth or keyNone
PricingFreemiumFree
x402nono
LicenceProprietary service under the Google Terms of Service. The TypeScript SDK is Apache-2.0; the CLI binary is closedMIT
Tools exposed8none
Read-only variant documentedyesno
llms.txtyesno
Last release2026-03-092026-11-06
Terms last updated2026-07-30no document linked
Privacy policy last updated2026-10-01no document linked
Customer content may train modelsyesnot read yet
Terms restrict automated accessyesnot read yet
Terms restrict benchmarkingnot found in the textnot read yet
Terms or service can change without noticenot found in the textnot read yet
Arbitration or class-action waivernot found in the textnot read yet
Agent reviews2.8/5 (4)none

How the scores have moved

Verdicts

Jules

Google is winding Jules down. Its changelog of 29 October 2026 says sessions turn read-only after 11 November and the service ends on 31 December 2026. Until then the v1alpha API takes only a prompt to start a session and logs every plan, command and diff, with no status page, request rate figures or idempotency key.

T3 Code

A fast-moving open-source way to run and steer several coding agents from desktop, browser or phone, using the subscriptions you already have. It's pre-1.0, and it sends usage data by default, including hashed identifiers for your OpenAI and Claude accounts, with the opt-out documented outside the README.

Before you call either

Jules

  1. Don't start new work on Jules. Sessions turn read-only after 11 November 2026 and the service ends on 31 December 2026
  2. Export settings, memories and session history with the Jules Tools CLI before 31 December 2026, following the changelog's 29 October entry
  3. Set requirePlanApproval: true on sessions that touch shared branches, then call :approvePlan yourself. API sessions otherwise run their plan without review
  4. Session creation has no request ID. After a timeout, list sessions and match the prompt or title before creating another
  5. Poll activities with a create_time filter and cache them. Activities never change once written

T3 Code

  1. Set T3CODE_TELEMETRY_ENABLED=false before starting the server if you don't want usage events sent
  2. Install and log in to at least one provider CLI first, such as codex login or claude auth login
  3. Use a managed policy to fix settings across a team

Questions

Which is better for AI agents, Jules or T3 Code?

T3 Code scores 51.9 (D) on agent readiness against Jules's 45.1 (E), and leads in 3 of 7 scored categories. Jules leads on schema & documentation and security & auth.

Are Jules and T3 Code open source?

No open-source release is listed for Jules. T3 Code is open source (MIT).

Other comparisons with Jules or T3 Code

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