Harness vs T3 Code

Harness 85

Read as an MCP server and CLI. Eleven tools in source at v0.5.33, each with a typed JSON Schema input built by one helper, required fields marked, plus --json on every command. No OpenAPI, which a stdio server does not need (23). llms.txt and a Markdown-like agents page written for agents, per the 17 October check, not re-read on 4 November, since Autonomous's terms forbid access to its sites by automated means, including scripts or web crawlers, and its hosts are paused pending the founder (10). The tool descriptions and server instructions say when to call whoami first, to prefer a new project over an existing folder, to read before telling a harness more, and that turning a setting on is the person's yes to give (20). An enum on agent and on the setting name, minItems on wait names, minimum and maximum on timeout_seconds, a minimum on chars and limit. machine, folder, project and model are free strings (12). Worked examples, the exit code table and the Next: line per the 17 October reading of the agents page and llms.txt, with exit codes still in the source (13). Per-component semver tags, but the only CHANGELOG.md covers the provider protocol (0.3.0, 6 August 2026), and GitHub's release pages could not be read (7). 23 + 10 + 20 + 12 + 13 + 7 = 85.

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).

Harness 40

No payment protocol (0). Read with the self-hosted rule. The software is free and the optional hardware prices are public, per the 17 October check, not re-read on 4 November, since Autonomous's terms forbid access to its sites by automated means, including scripts or web crawlers, and its hosts are paused pending the founder (20). Free with no card (20). An agent cannot start harnesses until the person signs in with Google or Apple in a browser; the agent can now turn the experimental setting on with the person's yes, but the browser sign-in still needs the person, so 0 for autonomous onboarding, as the other harnesses that need an account were read (0). 0 + 20 + 20 + 0 = 40.

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.

Harness 54

Harness reading of the framework checklist, as for the other harnesses. 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. Product usage counts are on by default, disclosed with an opt-out in the repository's measurement document (updated 31 October) and without prompts, code or files. Remote traffic is end-to-end encrypted and relays carry ciphertext. Local use needs no account. The daemon updates itself from a checksummed manifest without asking (18). Agents may start harnesses only with the account's Agents can start other agents setting on, with four live harnesses at most and closes limited to their own. Since v0.4.69_cli (26 October 2026) an agent can turn that setting, and the other agent settings, on itself with harness settings <name> on --person-said-yes or the harness_settings tool, after asking the person; the source says the yes is the agent's word and is logged with the agent's name. The tool carries no safe hint, and the command is not in Harness's allow rules, so the engine's own permission prompt still applies. Against that, installing Harness adds its other commands to Claude Code's and Codex's allow rules, Codex runs them outside its sandbox, there is no sandbox of its own, and the device page listed spoken tasks as auto-allowed on 17 October. 13 on 17 October, when an agent could not turn the setting on, so 10 now. The instructions tell an agent never to answer a harness's question or permission prompt. Harness output is another agent's text, and no further guidance on it was found (9). Every harness shows in the person's app with who started it, the device key log keeps an add and remove history, and an agent's settings change is named in the daemon's log. No per-call audit log found (9). SECURITY.md with an email and a three-working-day acknowledgement, and a documented trust model. No security.txt (17 October check), bug bounty or certification found. OSV lists no advisory for @autonomous-ai/harness-mcp (8). 18 + 10 + 9 + 9 + 8 = 54.

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.

Harness 77

Eleven tools at v0.5.33 (seven on 17 October). Added since then are harness_search, harness_machines, harness_tell and harness_settings; harness_send and harness_tell are listed only inside a harness, so an agent outside one sees nine. Descriptions total about 4,000 characters. Judgement call. By the total, 11 tools fall in the 11 to 30 band (15), with 5 back for listing two tools only inside a harness (20). Counting only the nine an outside agent sees gives 25. We took the stricter reading, as the 17 October check counted the total (20). chars sizes a read (4,000 characters by default), limit sizes a search (10 by default), all widens the list, and any returns on the first finished harness. No pagination (14). Exit codes, refusals returned as answers rather than errors so a model does not retry them, and a timed-out wait reported as still working, in the source (19). readOnlyHint on whoami, list, search, machines, wait and read, destructiveHint false on start, tell and send, idempotentHint on close, and no hint on settings so an engine that asks before an unmarked tool asks the person (16). Two required fields on start, defaults of Claude Code and a 45-second wait. No SDK, but a CLI, an MCP server and a plugin with a skill (8). 20 + 14 + 19 + 16 + 8 = 77.

T3 Code 60

Harness reading. Remote control from phone or browser, portable handoffs between providers and managed policies for teams (60).

Harness 64

MIT licence for the whole repository under Autonomous, Inc., with third-party Store covers under their own licences (30). The repository documents what usage counts contain, a 10-day pseudonymous activity mark and the encrypted relay in detail. Autonomous's privacy policy of 7 July 2026 is general to its stores and sites and does not mention Harness, per the 17 October reading and the site's policy reading of 30 October (14). The provider protocol promises both revisions side by side for a deprecation window after a breaking change. Nothing similar for the app or CLI (6). Telemetry is disclosed with an opt-out in the app and CLI, but it is on by default and described in the repository rather than in the privacy policy (14). 30 + 14 + 6 + 14 = 64.

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.