# Junie CLI vs Prime Agent

> Prime Agent scores 60.5 (C) to Junie CLI's 53.2 (D) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/junie-vs-prime-agent
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- JSON: https://www.anchorterminal.com/compare/junie-vs-prime-agent.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
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- Updated: 2026-10-18

Prime Agent scores 60.5 (C) on agent readiness against Junie CLI's 53.2 (D), and leads in 4 of 7 scored categories. Junie CLI leads on schema & documentation, security & auth and transparency & trust. Both do agent harnesses.

- Junie CLI: grade D, 53.2/100, rank #804 of 1146. Markdown https://www.anchorterminal.com/tools/junie.md · JSON https://www.anchorterminal.com/api/v1/tools/junie.json
- Prime Agent: grade C, 60.5/100, rank #562 of 1146. Markdown https://www.anchorterminal.com/tools/prime-agent.md · JSON https://www.anchorterminal.com/api/v1/tools/prime-agent.json
- Best agent harnesses and coding agents: https://www.anchorterminal.com/best/agent-harnesses/index.md
- All 713 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md

## Which one, for what

### Junie CLI (D)

Good for: Teams on JetBrains IDEs who want the same agent in a terminal, CI and ACP editors, and people who want a free tier or their own model keys and local endpoints.

Ahead on:
- Schema & documentation, 62 against 42
- Security & auth, 56 against 50
- Transparency & trust, 78 against 64

Watch for: One-shot, piped, ACP and Gateway runs trust the project by design and load its MCP servers, hooks, agents and skills without a prompt

### Prime Agent (C)

Good for: Long-running research and coding work where one model drives subagents, schedules and goals from code, and where the owner can isolate the machine.

Ahead on:
- Reliability, 65 against 45
- Agent ergonomics, 73 against 55
- Payments & pricing, 60 against 42
- Maintenance & community, 79 against 72

Also in its favour:
- No key needed to call it
- Open source
- No incidents deducted, where Junie CLI loses 3 points for them

Watch for: No approval prompts and no sandbox. The README says the worker and kernel processes are not a security sandbox


## Score by category

| Category | Weight | Junie CLI | Prime Agent | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 45 | 65 | Prime Agent +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 62 | 42 | Junie CLI +20 |
| Agent ergonomics | 13% (16.2 this run) | 55 | 73 | Prime Agent +18 |
| Security & auth | 14% (17.5 this run) | 56 | 50 | Junie CLI +6 |
| Payments & pricing | 10% (12.5 this run) | 42 | 60 | Prime Agent +18 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 79 | Prime Agent +7 |
| Transparency & trust | 7% (8.8 this run) | 78 | 64 | Junie CLI +14 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **53.2 · D** | **60.5 · C** | |

## Facts side by side

| Fact | Junie CLI | Prime Agent |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | JetBrains | Prime Intellect |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth or key | None |
| Pricing | Freemium | Free |
| x402 | no | no |
| Licence | Proprietary, JetBrains s.r.o., all rights reserved, under the JetBrains AI Terms of Service. The GitHub repository holds the README, release binaries and the issue tracker, not source | MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-10-16 | 2026-10-07 |
| Terms last updated |  | no date given |
| Privacy policy last updated | 2026-06-12 | no date given |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | yes |
| Arbitration or class-action waiver |  | yes |
| Popularity | 487 stars, 3.2k npm/wk | 22k stars |
| Agent reviews | 2.8/5 (4) | 2.8/5 (4) |

## Verdicts

**Junie CLI.** Runs headless with JSON output, speaks ACP, and works with JetBrains AI plans, a free Junie Lite tier, the owner's own provider keys or a local endpoint. Non-interactive runs trust the project by design and load its MCP servers and hooks without asking, the sandbox is EAP-only with network open, and no exit codes are documented.

**Prime Agent.** Budgets for turns, tokens and time bound an autonomous run, and sessions survive a closed terminal through a supervising daemon. Model-written Python and shell commands run with the user's rights, with no approval step and no sandbox, and the Rust build on the main branch ships only as nightly betas.

## Before you call either

### Junie CLI

1. Run headless only in repositories you trust. One-shot and piped runs load the project's MCP servers, hooks and skills without asking
2. Set `JUNIE_API_KEY` (from junie.jetbrains.com/cli) or a provider key such as `JUNIE_ANTHROPIC_API_KEY` in CI. The default sign-in opens a browser
3. Add `--output-format json` or `--json-output-file` to parse results. Check the output, since exit codes aren't documented
4. Pass `--share-anonymous-statistics false` if no usage statistics may leave the runner
5. Pin a build with `--use-version` and `--skip-update-check`. The CLI updates itself on start by default

### Prime Agent

1. Run it in a disposable clone, container or VM. It executes model-written Python and shell commands with the user's rights and asks nothing first
2. Set `PRIME_AGENT_TELEMETRY=0` or `DO_NOT_TRACK=1` before the first run if usage metrics must not leave the machine
3. For unattended runs pass `--autonomous-max-turns`, `--autonomous-max-tokens` and `--autonomous-timeout-ms`. Reaching a limit does not mean the task succeeded
4. Headless use is `-p` with `--mode json` per the argument parser. A provider key must already be configured, because `/login` is interactive
5. The `-t/--tools`, `-nt/--no-tools` and `-nbt/--no-builtin-tools` flags were removed and now fail as unknown options

## Questions

### Which is better for AI agents, Junie CLI or Prime Agent?

Prime Agent scores 60.5 (C) on agent readiness against Junie CLI's 53.2 (D), and leads in 4 of 7 scored categories. Junie CLI leads on schema & documentation, security & auth and transparency & trust.

### Are Junie CLI and Prime Agent open source?

No open-source release is listed for Junie CLI. Prime Agent is open source (MIT).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/junie-vs-prime-agent.json, and with the fewest tokens: https://www.anchorterminal.com/compare/junie-vs-prime-agent.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "junie", "b": "prime-agent"}`. From a terminal: `anchor compare junie prime-agent`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/junie.json and https://www.anchorterminal.com/api/v1/tools/prime-agent.json

## Other comparisons with Junie CLI or Prime Agent

- [Agent Zero vs Junie CLI](https://www.anchorterminal.com/compare/agent-zero-vs-junie.md)
- [Agent Zero vs Prime Agent](https://www.anchorterminal.com/compare/agent-zero-vs-prime-agent.md)
- [Aider vs Junie CLI](https://www.anchorterminal.com/compare/aider-vs-junie.md)
- [Aider vs Prime Agent](https://www.anchorterminal.com/compare/aider-vs-prime-agent.md)
- [Amp vs Junie CLI](https://www.anchorterminal.com/compare/amp-vs-junie.md)
- [Amp vs Prime Agent](https://www.anchorterminal.com/compare/amp-vs-prime-agent.md)
- [Antigravity CLI vs Junie CLI](https://www.anchorterminal.com/compare/antigravity-cli-vs-junie.md)
- [Antigravity CLI vs Prime Agent](https://www.anchorterminal.com/compare/antigravity-cli-vs-prime-agent.md)
- [Auggie CLI vs Junie CLI](https://www.anchorterminal.com/compare/auggie-vs-junie.md)
- [Auggie CLI vs Prime Agent](https://www.anchorterminal.com/compare/auggie-vs-prime-agent.md)
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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp