Head to head · Agent harnesses · October 2026 research run
Agent Zero vs T3 Code
T3 Code scores 51.9 (D) on agent readiness against Agent Zero's 46 (D), and leads in 0 of 7 scored categories. Agent Zero leads on reliability, schema & documentation, security & auth and transparency & trust. Both do agent harnesses.
Best agent harnesses and coding agents · All 1500 harnesses comparisons
Which one, for what
Best for A technical owner who wants an agent with its own Linux machine, reachable from Telegram, WhatsApp or email, with scheduled tasks and editable memory.
Ahead on
- Reliability, 57 against 43
- Schema & documentation, 64 against 55
- Security & auth, 54 against 35
- Transparency & trust, 64 against 51
Watch for
No approval step before shell commands, file changes or outgoing messages. Tool Access defaults to allow
T3 Code D
Best for Developers who want one app, including on their phone, to drive several coding agents they already pay for.
Also in its favour
- No incidents deducted, where Agent Zero loses 15 points for them
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.
Security & auth Agent Zero +19
Agent Zero 54
Harness reading of the framework checklist, the one the Goose calibration dossier uses. 30 for what leaves the machine by default, 20 for approvals and sandboxing, 15 for prompt-injection posture, 15 for audit and 20 for the security programme. No usage telemetry was found in the source. An update check, on by default, posts the version and a 20-character SHA-256 hash of a random per-install id to api.agent-zero.ai. The Update Checker settings page says only that ID and the version are sent and has an off switch. Something still leaves the machine by default, so the partial is kept (22). The agent works inside a Docker container built on Kali Linux and runs as root there. Tool Access can block tools by project or profile and defaults to allow, host access through the A0 CLI is scoped by read, write and execute permissions, and no approval step was found before a shell command, a file deletion or an outgoing message. The web interface has no login until a username is set (10). Infection Check audits the agent's reasoning with a second model before each tool call and ships disabled. Scanners check plugins, skills and MCP servers before install. The channel allow-lists accept every sender when empty, and the email filter matches the claimed From address only, which the plugin README states (7). Chat logs, visible tool steps and Time Travel snapshots, with no per-call audit log. Per-process log files were removed in v2.5 (9). No SECURITY.md on 4 November, security.txt answered 404 on 12 October, and none of the eight CVEs published from 17 March to 22 October 2026 came from the vendor (VulDB, VulnCheck, MITRE and CISA assigned them). A security-review ledger in the repository records two findings, and the v2.12 notes name both fixes (6, a partial kept).
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.
Reliability Agent Zero +14
Agent Zero 57
Read with the local-software lines, as software the owner runs. Installs from the agent0ai/agent-zero Docker image, an install script, or a desktop Launcher with builds for macOS, Linux and Windows on x86 and ARM64. The README says it runs wherever Docker runs. The image registry page was not read (17 of 20). The repository holds 245 files under tests/ on 4 November, and its only two workflows still publish Docker images and close inactive issues. The publish workflow runs no tests, so no public CI run shows them passing (5 of 25, a partial kept). 139 open issues and pull requests on 12 October 2026, per that check (GitHub's pages and API weren't read on 4 November). Open reports from September include a crash of run_ui after a failed memory consolidation (#1909), a browser worker that hangs the agent turn (#1923) and truncated backups (#1904), each with no reply or one, and a workflow closes anything inactive for 90 days (11 of 25). Release notes for v2.11, v2.12 and v2.13 carry a Breaking Changes section, but breaking changes ship in minor versions, so the numbering is not semver (9 of 15). v2.15, past 1.0 (15).
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.
Transparency & trust Agent Zero +13
Agent Zero 64
MIT, copyright Agent Zero, s.r.o. (30). No privacy policy for the software was found. The site's cookie notice covers the website, and its terms (14 May 2026) cover the community platform. The docs say where data lives (chats, memory, secrets and settings under /a0/usr) and warn that model providers see what is sent to them only in general terms, with no retention statement (8 of 30). Release notes list breaking changes and removals with the release date, and one deprecated alias is named. No deprecation policy or notice period was found (8 of 20, a partial kept). No usage telemetry was found in the source. The update check is described on its settings page, which says it sends only a randomised, hashed install ID and the version number, and the same page turns it off. The ID is a hash of a random per-install token, a pseudonym under this run's reading, so the statement holds (20). 30 + 8 + 8 + 20 = 66.
T3 Code 51
MIT (30). docs/user/telemetry.md lists what is sent and what isn't, but includes hashed third-party account identifiers and the README doesn't mention it (15 of 30). No deprecation policy (5). Disclosed with an opt-out, on by default (12 of 20). 30 + 15 + 5 + 12 = 62.
Schema & documentation Agent Zero +9
Agent Zero 64
Harness reading of the lines, as the Goose calibration dossier does. No OpenAPI file. The connectivity page lists five external endpoints and the X-API-KEY header, then sends readers to the source or DeepWiki for request and response details. Each API handler and tool has a .dox.md contract file in the repository, and the MCP client JSON shape is documented (10 of 25). llms.txt at www.agent-zero.ai, and AGENTS.md contract files across the repository (10). Guides say which path to use for a need, with tables that separate the browser, the host connector, MCP and A2A (14 of 20). The v2.12 notes say 15 bundled tools gained argument descriptions in non-strict schemas, and plugin settings are typed YAML with commented examples (8 of 15). Guides carry worked examples and a troubleshooting page, with no documented error responses for the external API (9 of 15). Dated notes on every GitHub release and a release article for each version on the site, with no version prefix on API routes (13 of 15).
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
| Category | Weight this run | Agent Zero | T3 Code | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 57 | 43 | Agent Zero +14 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 64 | 55 | Agent Zero +9 |
| Agent ergonomics | 13%16.2 | 62 | 60 | Agent Zero +2 |
| Security & auth | 14%17.5 | 54 | 35 | Agent Zero +19 |
| Payments & pricing | 10%12.5 | 60 | 60 | even |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 75 | 75 | even |
| Transparency & trust | 7%8.8 | 64 | 51 | Agent Zero +13 |
| Negative events | ≤15 | -15 | 0 | |
| Total | D 46/100 | D 51.9/100 |
Facts side by side
| Fact | Agent Zero | T3 Code |
|---|---|---|
| Kind | Agent harness | Agent harness |
| Vendor | Agent Zero, s.r.o. | T3 Tools Inc. |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | ||
| Auth | None | None |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | MIT | MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-11-01 | 2026-11-06 |
| Terms last updated | no document linked | no document linked |
| Privacy policy last updated | no document linked | no document linked |
| Popularity | 19k stars | none |
How the scores have moved
T3 Code
No score change since it was listed.
Verdicts
Agent Zero
Self-hosted under the MIT licence, with seven releases from 12 August to 1 November 2026 and breaking changes listed in minor-release notes. The agent runs shell commands in its container with no approval step, the web interface has no login by default, and eight CVEs from the past year were published by third parties with no vendor advisory.
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
Agent Zero
- Set a UI login and password in Settings before publishing the port or opening a tunnel. The default has none
- Fill
allowed_users,allowed_numbersorsender_whitelistbefore enabling a channel. An empty list accepts every sender - Enable the Infection Check plugin when the agent reads mail, web pages or MCP results. It ships disabled
- Run v2.12 or later. It fixes a Telegram webhook authentication bypass and a WhatsApp media path traversal
- Call
POST /api_messagewith theX-API-KEYheader. The token changes when the UI login or password changes
T3 Code
- Set T3CODE_TELEMETRY_ENABLED=false before starting the server if you don't want usage events sent
- Install and log in to at least one provider CLI first, such as codex login or claude auth login
- Use a managed policy to fix settings across a team
Questions
Which is better for AI agents, Agent Zero or T3 Code?
T3 Code scores 51.9 (D) on agent readiness against Agent Zero's 46 (D), and leads in 0 of 7 scored categories. Agent Zero leads on reliability, schema & documentation, security & auth and transparency & trust.
Are Agent Zero and T3 Code open source?
Yes. Agent Zero is open source (MIT). T3 Code is open source (MIT).
Other comparisons with Agent Zero or T3 Code
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- Agent Zero vs Junie CLI
- Agent Zero vs Kilo Code CLI
- Agent Zero vs Kimi Code CLI
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- Agent Zero vs Letta
- Agent Zero vs mini-swe-agent
- Agent Zero vs MiniMax Code
- Agent Zero vs Mistral Vibe CLI
- Agent Zero vs Muse Code
- Agent Zero vs OpenAI Agents API
- Agent Zero vs OpenAI Codex
- Agent Zero vs OpenCode
- Agent Zero vs OpenHands
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- Agent Zero vs Qwen Code
- Agent Zero vs Mirror CLI
- Agent Zero vs Rovo Dev CLI
- Agent Zero vs Sculptor
- Agent Zero vs Traycer
- Agent Zero vs Unstoppable
- Agent Zero vs Verdent
- Agent Zero vs Vibe-Trading
- Agent Zero vs Warp (Warp Agent CLI and the Oz Agent API)
- Aider vs T3 Code
- Amp vs T3 Code
- Antigravity CLI vs T3 Code
- Auggie CLI vs T3 Code
- AXLR vs T3 Code
- Claude Code vs T3 Code
- Cline vs T3 Code
- Conductor vs T3 Code
- Crush vs T3 Code
- Cursor CLI vs T3 Code
- DeepSeek Harness (dsh) vs T3 Code
- dsh-superagent (DeepSeek) vs T3 Code
- Devin vs T3 Code
- Droid CLI vs T3 Code
- Pi vs T3 Code
- Emdash vs T3 Code
- Gemini CLI vs T3 Code
- GitHub Copilot CLI vs T3 Code
- goose vs T3 Code
- Harness² vs T3 Code
- HarnessRouter vs T3 Code
- Jules vs T3 Code
- Junie CLI vs T3 Code
- Kilo Code CLI vs T3 Code
- Kimi Code CLI vs T3 Code
- Kiro CLI vs T3 Code
- Letta vs T3 Code
- mini-swe-agent vs T3 Code
- MiniMax Code vs T3 Code
- Mistral Vibe CLI vs T3 Code
- Muse Code vs T3 Code
- OpenAI Agents API vs T3 Code
- OpenAI Codex vs T3 Code
- OpenCode vs T3 Code
- OpenHands vs T3 Code
- Orca vs T3 Code
- Paseo vs T3 Code
- Prime Agent vs T3 Code
- Qoder CLI vs T3 Code
- Qwen Code vs T3 Code
- Mirror CLI vs T3 Code
- Rovo Dev CLI vs T3 Code
- Sculptor vs T3 Code
- T3 Code vs Traycer
- T3 Code vs Unstoppable
- T3 Code vs Verdent
- T3 Code vs Vibe-Trading
- T3 Code vs Warp (Warp Agent CLI and the Oz Agent API)
- Clawboo vs T3 Code
- CLI Manager vs T3 Code
- Harness vs T3 Code
- OpenMausBot vs T3 Code
- Paperclip vs T3 Code
- Parallax vs T3 Code
Machine-readable
- This page as Markdown
/compare/agent-zero-vs-t3-code.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/agent-zero.json·/api/v1/tools/t3-code.json - From a terminal
anchor compare agent-zero t3-code(the CLI) - Over MCP
compare_tools {"a": "agent-zero", "b": "t3-code"}at/mcp, no key