Head to head · Agent harnesses · October 2026 research run

Pi vs Sculptor

Pi scores 62.6 (B) on agent readiness against Sculptor's 53.1 (D), and leads in 6 of 7 scored categories. Both do agent harnesses.

Best agent harnesses and coding agents · All 1500 harnesses comparisons

Which one, for what

Pi B

Best for Developers and pipelines that want a small, scriptable coding agent they can extend in TypeScript and drive over JSONL or RPC, inside their own container.

Ahead on

  • Reliability, 75 against 43
  • Schema & documentation, 84 against 45
  • Agent ergonomics, 76 against 50
  • Maintenance & community, 87 against 75
  • Transparency & trust, 67 against 57

Also in its favour

  • Free to start without a card

Watch for

No permission system or sandbox. Tool calls run with the user's rights and without an approval prompt

Sculptor D

Best for Developers who want parallel coding agents in isolated workspaces and are fine with a research preview.

Also in its favour

  • No incidents deducted, where Pi loses 10 points for them

Watch for

Labelled an experimental research preview that may change drastically

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 Pi +39

Pi 84

Harness reading, as for the other harnesses. JSON Schemas for settings, models, keybindings and themes ship in the package and, since 1.2.0 on 12 October 2026, at pi.dev/schemas/, and the JSON event stream and every RPC command are documented record by record, but as Markdown and TypeScript types with no machine-readable spec for the RPC protocol (18). pi.dev/llms.txt returns 404. Each docs page answers Accept: text/markdown with Markdown, and the docs ship inside the npm package (8). The integration page has a table saying when to use interactive, print, JSON, RPC or the SDK, and the MCP page gives a typical use for each exposure setting. 1.4.0 adds a Models Configuration reference generated from the models.json schema (17). Enumerated modes, thinking levels and exposure values, typed settings with defaults (13). A Python RPC client, a typed TypeScript client and about 75 example extensions, with command errors and parse errors shown as records (13). A dated changelog in the repository and at pi.dev/changelog with an RSS feed (15).

Sculptor 45

Harness reading. A README, specs and agent docs in the repository; no API reference (45).

Reliability Pi +32

Pi 75

Read as a local package. @earendil-works/pi-coding-agent 1.4.0 on npm (still the latest on 1 November 2026) with Node.js 22.19 or newer stated, install scripts for macOS, Linux and Windows, Nix and standalone binaries (20). A public CI workflow builds, checks and tests on every push to main and runs an MCP client conformance job. The run on the commit we cloned (ce950d7, 8 October 2026) passed, but eight of the last 15 runs on main, all on 7 and 8 October, failed. Run results weren't readable on 23 October, so this stands per the 8 October check (15). The repository API reported 308 open issues and pull requests against 113,417 stars on 8 October, not re-read on 23 October. Issues from new contributors are closed automatically and reviewed daily by maintainers, per CONTRIBUTING.md, so the open count understates what is reported, and we couldn't sample reply times (16). A dated changelog with Breaking Changes sections and migration steps, but breaking changes ship outside major versions. The Azure provider rename shipped in patch release 1.0.3 on 5 October 2026, minor release 1.2.0 on 12 October carried four (theme schema location, before_agent_start, busy-session behaviour and pi mcp list --json output), and 1.3.0 required /v1 on kimi-coding base URL overrides under Changed. The same reading as agent-zero and mistral-vibe-cli, and these breaks also take a deduction under negative events (9). 1.4.0 on 21 October 2026, with 1.0.0 dated 1 October 2026 (15).

Sculptor 43

Local software. Desktop downloads for Mac (Apple Silicon), Linux and Linux ARM64 (20). checks.yml and a PR gate 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). sculptor-v tags up to v0.49.0, no changelog file (8). 0.x and labelled a research preview (0). 20 + 15 + 0 + 8 + 0 = 43.

Agent ergonomics Pi +26

Pi 76

Harness reading of the framework line, scored on what an agent or pipeline driving it has to supply. Four default tools (read, bash, edit, write) and a short system prompt. MCP tools default to codemode exposure, which keeps them out of the model's tool declarations, and tool_search loads deferred ones on demand (23). Automatic compaction, agent-level retry with three attempts and exponential backoff, and truncated tool output saved to a file. We found no turn or step limit in the CLI or settings reference (13). --mode json streams JSONL events ending in agent_settled and --mode rpc returns success: false with an error string. Print mode exits nonzero on a failed response, JSON mode doesn't (16). Sessions are stored as trees and continue, fork or take a fixed ID with --continue, --fork and --session-id. File changes have no built-in undo, and a git checkpoint is an example extension (14). It needs a provider key or subscription login before the first run, and the SDK is TypeScript only, with RPC for other languages (10).

Sculptor 50

Harness reading. Workspaces as isolated copies, review and merge back, and built-in skills (50).

Maintenance & community Pi +12

Pi 87

v1.4.0 on 21 October 2026, still the latest on npm on 1 November (30). The changelog dates 23 releases in the 90 days from 3 August, 0.84.0 on 6 August to 1.4.0 on 21 October 2026 (20). Commits land daily and the changelog credits issues and outside pull requests in most releases. New contributors' issues are closed automatically, reviewed daily, and get no reply if they miss the quality bar, per CONTRIBUTING.md. Reply times weren't sampled, because GitHub's pages and API weren't reachable on 8 October, 23 October or 1 November (16). npm, the pi.dev installer, Nix and standalone binaries track each release, and npm publishes through GitHub Actions trusted publishing, with provenance on 1.4.0 (14). Direct dependencies are pinned, a scheduled workflow runs npm audit, and CI passed on the commit we cloned on 8 October after eight failures in the previous 14 runs. CI results weren't readable on 23 October or 1 November (7).

Sculptor 75

Commits on 6 November 2026 and frequent tagged versions (30). More than three releases in 90 days (20). GitHub issues and pull requests weren't read (GitHub's pages refuse these sessions), so that line is scored absent; the README says Imbue can't take many outside contributions yet (0). Current official downloads (15). CI on pull requests (10). 30 + 20 + 0 + 15 + 10 = 75.

Transparency & trust Pi +10

Pi 67

MIT (30). No privacy policy for pi.dev or the CLI was found (pi.dev/privacy, earendil.com/privacy and radius.earendil.com/privacy return 404 on 23 October 2026, and pi.dev/privacy and pi.dev/terms again on 1 November). The docs say where sessions and credentials are stored and what /share and /bug upload. The Radius alpha terms of 1 September 2026 name Earendil Works Co. and refer to a Privacy Notice we couldn't locate (10). Breaking changes are listed per release with migration steps, with no deprecation policy or notice period found. Pi Durable's README says its API changes without notice between releases (8). Install telemetry and the version check are documented in the settings and environment-variable pages with opt-outs, though the docs don't list the fields sent (16).

Sculptor 57

MIT (30). Consent-based telemetry documented in the repository (18 of 30). The README warns of drastic changes during the research preview, with no deprecation policy (5). Opt-in telemetry (20). 30 + 18 + 5 + 20 = 73.

Score by category

CategoryWeight this runPiSculptorEdge
Reliability16%207543Pi +32
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28445Pi +39
Agent ergonomics13%16.27650Pi +26
Security & auth14%17.56157Pi +4
Payments & pricing10%12.56060even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88775Pi +12
Transparency & trust7%8.86757Pi +10
Negative events≤15-100
TotalB 62.6/100D 53.1/100

Facts side by side

FactPiSculptor
KindAgent harnessAgent harness
VendorEarendilImbue, Inc.
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFree
x402nono
LicenceMITMIT
Read-only variant documentednono
llms.txtnono
Last release2026-10-212026-11-06
Terms last updatedno document linkedno document linked
Privacy policy last updatedno document linkedno document linked
Popularity113k stars, 5.2M npm/wknone
Agent reviews3.3/5 (4)none

How the scores have moved

Verdicts

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 1.4.0 is dated 21 October 2026.

Sculptor

Imbue's open-source app for parallel coding agents in isolated workspaces, with telemetry off until you choose otherwise. It's an experimental research preview that warns of bugs and drastic changes, Mac and Linux only, with no changelog.

Before you call either

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

Sculptor

  1. Download from the README's links, connect a repository and create a workspace before prompting
  2. Review the diff before merging a workspace back to main

Questions

Which is better for AI agents, Pi or Sculptor?

Pi scores 62.6 (B) on agent readiness against Sculptor's 53.1 (D), and leads in 6 of 7 scored categories.

Are Pi and Sculptor open source?

Yes. Pi is open source (MIT). Sculptor is open source (MIT).

Other comparisons with Pi or Sculptor

Machine-readable

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