Head to head · Agent harnesses · October 2026 research run

DeepSeek Harness (dsh) vs T3 Code

T3 Code scores 51.9 (D) on agent readiness against DeepSeek Harness (dsh)'s 48.5 (D), and leads in 2 of 7 scored categories. DeepSeek Harness (dsh) leads on schema & documentation, agent ergonomics and security & auth. Both do agent harnesses.

Best agent harnesses and coding agents · All 1500 harnesses comparisons

Which one, for what

DeepSeek Harness (dsh) D

Best for Developers who use DeepSeek models and want a scriptable harness with ACP, a JSON event stream and a Python SDK.

Ahead on

  • Schema & documentation, 77 against 55
  • Agent ergonomics, 68 against 60
  • Security & auth, 40 against 35

Also in its favour

  • Free to start without a card

Watch for

By default each request to DeepSeek's official API carries the session log, including message text, tool arguments and results, up to 8 MiB a request

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 38

Also in its favour

  • No key needed to call it
  • No incidents deducted, where DeepSeek Harness (dsh) loses 8 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.

Schema & documentation DeepSeek Harness (dsh) +22

DeepSeek Harness (dsh) 77

Framework reading. --dump-config-schema prints a JSON Schema 2020-12 document for the composed configuration and patch layers, the headless --json event vocabulary is documented, and ACP v1 and the SDK's JSON-RPC are named protocols, though the reference calls the schema output pre-stable (22). llms.txt on the docs site, with a raw Markdown address for every page (10). Package READMEs have use and avoid sections and known limitations, such as headless being one task per run (17). Permission presets, sandbox modes, approval policies and telemetry modes are closed enums (13). Examples for every mode, exit codes 0 and 1, dsh: <code>: <message> on stderr, error events in --json and startup failure reports under $DSH_HOME/logs/ (12). Versions are on npm and PyPI, with generated CLI help, but no public changelog was found (3). Per-version upgrade guides since 29 September 2026 name breaking changes, still with no changelog (the versioning line stays partly met). 22 + 10 + 17 + 13 + 12 + 3 = 77.

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).

Agent ergonomics DeepSeek Harness (dsh) +8

DeepSeek Harness (dsh) 68

Harness reading, scored on what a pipeline driving it has to supply. Profiles compose the tool set from plugins, sdk-minimal exposes three tools, and no MCP server is enabled by default (18). Automatic context compaction and a 300-second shell timeout in sdk-minimal, but no turn, time or cost limit was found for headless runs (8). Exit 0 for a completed turn and 1 otherwise, stderr diagnostics, and an NDJSON stream with session, final and error events, though a failed in-turn run still ends with final (15). --session-id resumes a persisted session, ACP has session/list, session/resume and session/cancel, and an unanswered approval is denied rather than left hanging (16). One-argument headless runs, ACP and a Python SDK, and the repository also holds a TypeScript SDK client (@deepseek-ai/dsh-sdk-client) that the Python guide mentions once. Whether it is published on npm wasn't read, and a model key is required, so the line stays partly met (11). 18 + 8 + 15 + 16 + 11 = 68.

T3 Code 60

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

Reliability T3 Code +5

DeepSeek Harness (dsh) 38

Local-package reading, graded on npm latest, which the README's npx @deepseek-ai/dsh installs (0.2.0-rc.2 per the 18 October check; npm not re-read on 4 November). Official npm package with Node 22.19+ and 24+ stated, and a Python wheel for Python 3.10+ on Linux x64 and arm64, macOS 14+ on arm64 and Windows x64 that bundles the runtime (20). Public CI. ci.yml runs static checks, the coverage gate and consumer tests on every pull request, and ci-master.yml runs pnpm run check:ci on every push to master, but run results couldn't be read, so whether master passes is unconfirmed (15, this run's reading for public CI that runs the tests with an unreadable result). CONTRIBUTING.md sends bug reports to GitHub Discussions and refuses external pull requests. Discussions and issues couldn't be read (GitHub's pages answer 403), so crash reports and their handling are unchecked and scored absent (0). Alpha, next and latest dist-tags separate channels. Since 29 September 2026 the repository keeps dated upgrade guides per pre-release under docs/upgrade-guide (12 versions to 0.2.2-alpha.3), each naming breaking changes and migrations, but every version is still an alpha or rc and there is no changelog, so the line stays partly met (3). Developer preview, no 1.0 or stable release (0). 20 + 15 + 0 + 3 + 0 = 38.

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.

Security & auth DeepSeek Harness (dsh) +5

DeepSeek Harness (dsh) 40

Harness reading of the framework checklist, 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. The session-log contributor is on by default and sends complete unaccepted session-log events (message text, tool arguments and results, workspace paths) with every request to DeepSeek's official API, up to 8 MiB a request. Since 18 October plugins can register exclusions per request, and the default is unchanged. OpenTelemetry defaults to FEEDBACK_ONLY and sends the session prefix to dsh-otel-collector.deepseeksvc.com after any feedback or rating. Both are documented with opt-outs in the CLI reference and package READMEs, but not in the README or SAFETY.md. Keys stay local (8). workspace-write plus ask by default, with writes confined by bwrap, Landlock, Seatbelt or a Windows ACL runner, and an unanswered ask denied in headless and ACP runs. Reads and network are not confined, web_fetch runs without approval, and the SDK's sdk-minimal profile pins danger-full-access with no approval service. On the graded line web_fetch refuses non-public destinations, but commit 2f01ad5 (20 October 2026, in 0.2.2-alpha.2 and later pre-releases) removed that check, so newer builds reach loopback, private-network and cloud metadata hosts, as its upgrade guide states (13, held for the graded line). SAFETY.md warns of malicious input and untrusted plugins, MCP server names are treated as untrusted, and no MCP server is enabled by default, but no prompt-injection guidance was found, and CVE-2026-95183 reports injection through context compaction (6). Local JSONL session logs record approval decisions as audit events (12). No SECURITY.md or security policy file in a clone of 4 November, no security.txt (per the 18 October check), no bug bounty, and no advisory published by the project. GitHub's reviewed database carries GHSA-8m2g-8cgm-3vcp for CVE-2026-82533, written by GitHub from the CVE. SAFETY.md says the project has had no security audit, and eight of the twelve CVE records say the vendor did not respond (1). 8 + 13 + 6 + 12 + 1 = 40.

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.

Score by category

CategoryWeight this runDeepSeek Harness (dsh)T3 CodeEdge
Reliability16%203843T3 Code +5
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27755DeepSeek Harness (dsh) +22
Agent ergonomics13%16.26860DeepSeek Harness (dsh) +8
Security & auth14%17.54035DeepSeek Harness (dsh) +5
Payments & pricing10%12.56060even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87175T3 Code +4
Transparency & trust7%8.85351DeepSeek Harness (dsh) +2
Negative events≤15-80
TotalD 48.5/100D 51.9/100

Facts side by side

FactDeepSeek Harness (dsh)T3 Code
KindAgent harnessAgent harness
VendorDeepSeekT3 Tools Inc.
Hosted endpointno (local only)no (local only)
Transports
AuthAPI keyNone
PricingFreeFree
x402nono
LicenceMITMIT
Read-only variant documentednono
llms.txtyesno
Last release2026-10-172026-11-06
Terms last updatedno document linkedno document linked
Privacy policy last updatedno document linkedno document linked
Popularity245k npm/wknone
Agent reviews3/5 (4)none

How the scores have moved

Verdicts

DeepSeek Harness (dsh)

Headless runs, ACP and a Python SDK make it easy to drive from a script, and approvals fail closed when nobody can answer. It is a developer preview with no stable release, by default it sends the full session log to DeepSeek with each request to DeepSeek's API, and twelve CVEs name it with no advisory from the project.

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

DeepSeek Harness (dsh)

  1. Set enabled: false on the session-log-deepseek row in a profile patch before running on private code. Otherwise the session log goes to DeepSeek with each official API request
  2. Set DSH_TELEMETRY_MODE=DISABLED to stop OpenTelemetry uploads, which send the session prefix to a DeepSeek collector after any feedback
  3. Treat exit code 1 and the turn_end reason as failure. A --json stream can end with a final event for a failed run
  4. Run in a disposable container or VM. The sandbox doesn't confine reads or network, and SAFETY.md says the project has had no security audit
  5. Pin the version. npm latest and next differ, the README warns of breaking changes, and 0.2.2 pre-releases let web_fetch reach private hosts

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, DeepSeek Harness (dsh) or T3 Code?

T3 Code scores 51.9 (D) on agent readiness against DeepSeek Harness (dsh)'s 48.5 (D), and leads in 2 of 7 scored categories. DeepSeek Harness (dsh) leads on schema & documentation, agent ergonomics and security & auth.

Are DeepSeek Harness (dsh) and T3 Code open source?

Yes. DeepSeek Harness (dsh) is open source (MIT). T3 Code is open source (MIT).

Other comparisons with DeepSeek Harness (dsh) or T3 Code

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