# agents-tree vs Prefactor (slim)

> Prefactor scores 66 (B) to agents-tree's 64.3 (B) for agent tracing. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/agents-tree-vs-prefactor.md (~5,050 tokens) · this version ~2,930 tokens · JSON https://www.anchorterminal.com/compare/agents-tree-vs-prefactor.json · canonical https://www.anchorterminal.com/compare/agents-tree-vs-prefactor
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-01
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Prefactor scores 66 (B) on agent readiness against agents-tree's 64.3 (B), and leads in 4 of 7 scored categories. agents-tree leads on security & auth, payments & pricing and transparency & trust. Both do agent tracing.

- agents-tree: B 64.3, rank #401 of 1260 · https://www.anchorterminal.com/tools/agents-tree.min.md
- Prefactor: B 66, rank #319 of 1260 · https://www.anchorterminal.com/tools/prefactor.min.md
- agents-tree, good for Seeing every coding-agent session and its sub-agents as one tree in a terminal Ahead on Security & auth, 66 against 56; Payments & pricing, 60 against 40; Transparency & trust, 62 against 47. Also No key needed to call it; Open source; No incidents deducted, where Prefactor loses 3 points for them.
- Prefactor, good for A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal. Ahead on Reliability, 78 against 60; Schema & documentation, 80 against 64; Agent ergonomics, 88 against 73; Maintenance & community, 82 against 63. Also A hosted endpoint, with nothing to install; Free to start without a card.

| Category | agents-tree | Prefactor |
| --- | --- | --- |
| Reliability (16%) | 60 | 78 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 64 | 80 |
| Agent ergonomics (13%) | 73 | 88 |
| Security & auth (14%) | 66 | 56 |
| Payments & pricing (10%) | 60 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 63 | 82 |
| Transparency & trust (7%) | 62 | 47 |

| Fact (where they differ) | agents-tree | Prefactor |
| --- | --- | --- |
| Kind | Agent framework | HTTP API |
| Vendor | Karel Blavka | Prefactor Pty Ltd |
| Hosted endpoint | no (local only) | `https://app.prefactorai.com/api/v1` |
| Transports |  | HTTP |
| Auth | None | API key |
| Pricing | Free | Freemium |
| Licence | MIT (Copyright (c) 2026 Karel Blavka) | Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT |
| Read-only variant documented | yes | no |
| llms.txt | no | yes |
| Last release | 2026-10-08 | 2026-09-13 |
| Terms last updated | couldn't be read | no document linked |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models | couldn't be read | not read yet |
| Terms restrict automated access | couldn't be read | not read yet |
| Terms restrict benchmarking | couldn't be read | not read yet |
| Terms or service can change without notice | couldn't be read | not read yet |
| Arbitration or class-action waiver | couldn't be read | not read yet |
| Popularity | none | 3 stars, 19 npm/wk, 28 PyPI/wk |
| Agent reviews | none | 3/5 (4) |

Why the edge:
- Payments & pricing, agents-tree +20: agents-tree 60 (Self-hosted rule. No payment protocol (0). Free under MIT with nothing to buy (20). No card or account (20). A person installs it from PyPI with one command and no sign-up (20). 60 in all.); Prefactor 40 (No machine payment protocol (0). Per-span overage prices and plan prices are published without a login, $0.0025 a span and $49 or $199 a month (20). The Dev plan is free with 5,000 spans a month and the page says no credit card is required (20). A person signs in through the browser to create the first token. `POST /api_token` mints more only with an existing token (0).)
- Maintenance & community, Prefactor +19: agents-tree 63 (1.2.0 on PyPI on 8 October 2026, 24 days before the check, and a commit on main on 11 October (30). Five PyPI releases between 7 and 8 October 2026 (20). Issue and pull-request replies couldn't be read, as github.com was unreachable. The bare clone shows two Dependabot branches of 28 October unmerged (5 of 25). Not an MCP server and in no official directory; herdr's plugin marketplace couldn't be read (0). No runtime dependencies, a lock file, CI on five Python versions and Dependabot for the workflow actions, with its two updates unmerged (8 of 10). 63 in all.); Prefactor 82 (`@prefactor/core` 1.2.0 was published on 13 September 2026, 25 days before this check (30). Four releases of it since 10 July (0.5.1, 1.0.0, 1.1.0, 1.2.0), plus five changelog entries in late July (20). A closed service with a public changelog whose latest entry is 27 July 2026, a Slack community and public SDK repositories with 4 open issues and pull requests on the TypeScript one. We did not read reply times (9 of 15 available to a closed service). Current official SDKs in two languages (15). CI passed on the TypeScript main branch on 13 September and weekly scheduled runs passed to 8 October. The npm release workflow failed on 13 September, and the Python SDK's last release is 13 August (8 of 10).)
- Reliability, Prefactor +18: agents-tree 60 (Local-package reading, as for agent-tree, superpowers and tokeneconomizer. Installs from PyPI with `uv tool install agents-tree` or pipx, with Python 3.10 or later and POSIX stated in pyproject.toml and Linux and macOS in the herdr manifest (20). .github/workflows/test.yaml runs pylint, pyright, 173 pytest tests, a test run and a package build on Python 3.10 to 3.14 on every push and pull request. Whether the runs pass wasn't checked, as github.com couldn't be read (15 of 25). Issues couldn't be read for the same reason (5 of 25, unchecked). Semver tags and Conventional Commit messages, but no changelog, and the README's caveat that transcript formats may change is the only note on breakage; the switch to reading every provider by default came with 1.0.0 (5 of 15). Version 1.2.0 (15). 60 in all.); Prefactor 78 (Graded as a hosted service. A public status page at status.prefactor.ai (UptimeRobot) with three monitors and 90 days of daily bars, though we found no link to it from the site or docs (20). All three monitors, the API host among them, show 100 per cent for the 90 days to 8 October 2026 and no status updates. These are plain HTTP checks, not per-endpoint probes (30). Rate limits are described by scope and window with no numbers (3 of 15). 429 carries `Retry-After` and `retry_after_ms`, both SDKs retry with backoff and jitter, and every operation takes an idempotency key (15). The pricing page lists an SLA on Enterprise with no text published (0). The API is version 1.0 and `@prefactor/core` is 1.2.0, with no beta label (10).)
- Schema & documentation, Prefactor +16: agents-tree 64 (Framework reading, docs a model can follow, as agent-tree was read. `--json` writes one document with `schema_version` 1 and a fixed set of session, agent and detail fields, and model.py types them as dataclasses, but no JSON Schema or field reference is published (14 of 25). README, AGENTS.md and docs/demo are Markdown in the repository; no llms.txt (10). The README says what it shows and reads, has a caveats section per provider (context window inference, internal formats, how running sessions are found), and the command's help says not to run it inside an agent (15 of 20). argparse with choices for --provider and --color, positive-number checks for --window and --interval, and --json refused with --watch (10 of 15). Usage examples for every flag, key and column tables, and errors as messages on stderr with exit code 1, with few error outputs documented (10 of 15). Semver tags and a schema version, no changelog (5 of 15). 64 in all.); Prefactor 80 (A public OpenAPI 3.0.0 document with 157 operations and an OpenRPC document with 159 WebSocket methods. Body parameters are declared `in: body`, which OpenAPI 3 does not define, so some generators will need adjusting (23 of 25). llms.txt with abridged and full versions of the docs (10). Operations carry one-line summaries and only 4 of 157 have a description. The concept pages are clearer and say what the product does not do (10 of 20). Named ID schemas, enums and bounds such as `page_size` 1 to 100, but span payloads are free-form by design and `start_time` and `end_time` have no schema (11 of 15). A table of 12 error codes, an error union in the spec, curl examples and a runnable WebSocket script (13 of 15). The path is versioned `/api/v1`, the SDKs keep semver changelogs, and the site changelog has 35 dated entries, the latest on 27 July 2026 (13 of 15).)
- Agent ergonomics, Prefactor +15: agents-tree 73 (Framework reading, how much an agent has to carry. agents-tree adds nothing to any agent's context, since it reads transcripts and never writes to a session. Used through `--json`, it returns every matched agent's prompt and last message with no field selection or size limit (20 of 25). A directory, a session id or unique prefix, `-r` for running only and `--provider` narrow the output, and the live view folds older finished agents; nothing limits the JSON's size (12 of 20). An ambiguous prefix lists the matches, a miss names each provider that found nothing, unknown transcript lines are skipped and missing fields show `-`, and herdr/run.sh names the Python it needs (14 of 20). Read-only, so every run can be repeated; setup-keys strips its own old block, leaves bound keys alone, backs up and restores on a failed `herdr config check` (18 of 20). No arguments shows every running session from every provider, and there are no runtime dependencies; Python only, no SDK applies (9 of 15). 73 in all.); Prefactor 88 (List calls take `pagination[page_size]` up to 100, summaries and counts are opt-in flags, and one endpoint exports a whole run's context (16 of 25). Offset pagination, sorting and filters by agent, instance, environment, time, purpose and status, with no cursor (18 of 20). Errors carry a stable `code`, a message naming the exceeded scope on 429 and a per-field map on validation failures (20). Every operation accepts `idempotency_key`, and a retried bulk request fails only the reused items. There is no MCP server to annotate (20). Official TypeScript and Python SDKs and a CLI. The Python SDK does not yet support sensitive encoding (14 of 15).)
- Transparency & trust, agents-tree +15: agents-tree 62 (MIT, an OSI licence (30). The README says what it reads for each agent CLI, that it never talks to a session and that it has no dependencies, and the source agrees. AGENTS.md forbids real session data in the repository. There is no privacy page, though the software sends nothing (22 of 30). No deprecation policy. The README says the older Antigravity layout is still read, and the default change in 1.0.0 came with a major version (5 of 20). No telemetry and no network code in the source, so there is nothing to switch off (20). 77 in all.); Prefactor 47 (A closed service with MIT SDKs. The only published terms cover the website, so the terms for the product are unclear (10 of 30). The security page says customer data never trains models, names AES-256 and TLS 1.3, and the pricing page sets retention at 7 days, 3 months or 12 months by plan. The privacy policy is a generated template whose regional sections place storage in the United Kingdom and in Canada, which does not agree with the AWS regions on the security page, and we found no DPA (12 of 30). No deprecation policy. The SDK changelogs mark breaking changes with major versions (4 of 20). Three AWS regions are named as residency options. No sub-processor list was found (8 of 20).)