Pi vs Prime Agent

Pi

Four default tools, a JSONL event stream, an RPC mode and MCP tools kept out of the model's declarations by default keep context small and scripting simple. Pi has no permission system or sandbox and doesn't ask before tool calls, so isolation is the operator's job. Version 1.0.0 is dated 1 October 2026.

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.

Pi

1. Run Pi inside a container or VM for unattended work. It has no sandbox and doesn't ask before running shell commands
2. Use pi --mode json and wait for agent_settled. A failed response doesn't set a nonzero exit code in JSON mode
3. Split the JSONL stream on LF only. Node's readline also splits on U+2028 and U+2029, which are valid inside JSON strings
4. Pass --no-approve or --approve in scripts to make the project trust decision explicit
5. Set PI_TELEMETRY=0 and PI_SKIP_VERSION_CHECK=1, or PI_OFFLINE=1, to stop the default requests to pi.dev

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