Capabilities and access

Aethis has exactly two access tiers. Everything on this site belongs to one of them, and every page says which before you start.

	Evaluate	Author and publish
Access	Open. No signup, no Aethis key, no model-provider key.	Invite-only private beta. Request access.
What you can do	Decide against published public rulesets, read their input schema, read their rules and source references, render their graph, diagnose a failed outcome, browse the public catalogue.	Everything above, plus create projects, upload sources, discover sections and fields, generate rules, run tests, review, and publish.
What it costs you	Nothing. Anonymous callers are rate-limited per client, with client identity taken from the trusted proxy hop rather than a caller-supplied header.	An Aethis API key, plus your own model-provider key for generation steps.
Where to start	Your first decision	Author your first ruleset

Generation steps send your source text to a model provider using your own key, passed per request in an X-Anthropic-Key header and never stored. Nothing on the evaluate tier calls a model at all — decisions run against pre-compiled rules.

What a 401 or 403 means

An authentication error on this API is a statement about which tier you are in, not a bug in your request.

Status	What happened	What to do
`401`	You called an authoring or tenant-scoped route with no key, or with a key the engine could not verify. Composed rulebook decisions (`rulebook_id`) are always in this class.	Evaluating a public ruleset? Use `ruleset_id` with a leaf slug — no key needed. Authoring? Request access.
`403`	Your key is valid but lacks the scope the route requires.	Check `aethis whoami` for your scopes, then see Authentication and API keys. Missing an authoring scope you were expecting? Request access.

The full status table, including the blocking-error contract, is on the REST API page.

Published packages

Four interfaces call the same engine. These are the versions the registries resolve today.

Surface	Package	Install	Latest published
CLI	`aethis-cli` (PyPI)	`uv tool install aethis-cli`	`0.29.0`
Python SDK	`aethis-sdk` (PyPI)	`uv add aethis-sdk`	`0.10.0`
MCP server	`aethis-mcp` (npm)	`npx -y aethis-mcp`	`0.15.1`

The REST API needs no package at all — see REST API.

MCP tool inventory

The MCP server (io.github.aethis-ai/aethis-mcp) exposes 32 tools: 7 are reachable with no Aethis API key (read-only evaluation and discovery) and 25 need an invite-only authoring key. Access is the tier a tool belongs to. “Any origin, hybrid” marks a tool whose common path is open but which has a narrower key-guarded path as well — aethis_graph renders a public ruleset map anonymously, but a rulebook map requires a key. Effect reproduces the readOnlyHint / destructiveHint annotations the server declares for each tool.

Treat the Effect column as a hint, not a safety boundary. It reports what the server declares about a tool, and a declaration can be wrong — a tool that spends your model-provider key and persists its result to your project can still be declared read-only. If your agent host gates approval on these annotations, do not rely on them alone to decide what may run unattended. Gate on the Access column as well, and treat every API-key tool as capable of writing.

Tool	What it does	Access	Effect
`aethis_add_domain_guidance`	Add a guidance hint at domain level — applies to ALL projects in the domain, not just one project	API key	Writes
`aethis_add_guidance`	Add a guidance hint to a project	API key	Writes
`aethis_archive_project`	Archive a project	API key	Retires content
`aethis_archive_ruleset`	Archive a rule ruleset	API key	Retires content
`aethis_create_rulebook`	Create a new Rulebook — the composed-whole execution unit that bridges multiple rulesets (the parts) via outcome_logic	API key	Writes
`aethis_create_ruleset`	Create a new rule ruleset with source text and test cases (TDD)	API key	Writes
`aethis_decide`	Evaluate eligibility against either a single published ruleset (ruleset_id) or a composed rulebook (rulebook_id)	No key	Read-only
`aethis_discover_fields`	Discover input fields from the project’s source text	API key	Read-only
`aethis_discover_rulesets`	List public showcase rulesets across all tenants	No key	Read-only
`aethis_discover_sections`	Discover the logical sections of source legislation for a domain	API key	Read-only
`aethis_explain`	Get human-readable descriptions of the rules in a ruleset, including criteria groups, requirements, and exception paths.	No key	Read-only
`aethis_explain_failure`	Diagnose why a ruleset produced an unexpected outcome for specific test inputs	No key	Read-only
`aethis_generate_and_test`	Generate rules from source text and run all test cases	API key	Writes
`aethis_graph`	Get the ruleset-map graph for a single published ruleset (ruleset_id) or a composed rulebook (rulebook_id) — provide exactly one	Any origin, hybrid	Read-only
`aethis_list_domain_guidance`	List all active guidance hints for a domain	API key	Read-only
`aethis_list_guidance`	List all guidance hints accumulated for a project	API key	Read-only
`aethis_list_projects`	List all projects in the current tenant	API key	Read-only
`aethis_list_rulebooks`	List rulebooks (composed wholes that bridge multiple rulesets) in the current tenant	API key	Read-only
`aethis_list_rulesets`	List all rule rulesets for a project, including version history	API key	Read-only
`aethis_next_question`	Get the optimal next question for a conversational eligibility check	No key	Read-only
`aethis_publish`	Publish the latest rule ruleset	API key	Writes
`aethis_refine`	Refine an existing published ruleset: add optional feedback, then make the MINIMAL edit to fix failing test cases while keeping passing tests green, and re-run	API key	Writes
`aethis_refine_fields`	Add guidance to improve field discovery, then re-discover	API key	Writes
`aethis_refine_sections`	Add guidance to improve section discovery, then re-discover sections	API key	Writes
`aethis_review_project`	Review an authoring project against the deterministic authoring-coach rubric and get skill-building feedback	API key	Read-only
`aethis_rulebook_schema`	Get the composition + aggregated input fields for a rulebook	API key	Read-only
`aethis_schema`	Get the input fields required for an eligibility check	No key	Read-only
`aethis_set_field_spec`	Store the expected field specification for a project	API key	Writes
`aethis_update_rulebook`	Update a Rulebook’s name, description, slug, or robot_hints (assistant guidance for the conversational agent)	API key	Writes
`aethis_usage`	Show the caller’s rate-limit budget per operation class over the rolling 24h window: for each of decide / generate / author / read / keys / admin, the used coun	API key	Read-only
`aethis_validate_fields`	Assert that the discovered fields match an expected field specification	API key	Read-only
`aethis_validate_sections`	Compare discovered sections against an expected specification	API key	Read-only

Parameters, request shapes and worked examples for each tool: Tools reference.

How these numbers stay true

The table above is not maintained by hand. scripts/gen_capability_inventory.py builds generated/capability-inventory.json from three checked upstream sources — the MCP server’s own generated tool-inventory.json, its TOOL_CAPABILITIES registry (which its test suite pins against the handlers that actually require a key), and the PyPI and npm registries. A CI check re-renders these regions on every pull request and fails if a page has drifted from the artefact, or if any page reintroduces a hand-typed tool count.

Getting started (no key)

AI coding agents

Interfaces

Recipes

Authoring (invite-only)

Reference

Changelog

Capabilities and access

What a 401 or 403 means

Published packages

MCP tool inventory

How these numbers stay true

​What a 401 or 403 means

​Published packages

​MCP tool inventory

​How these numbers stay true

What a 401 or 403 means

Published packages

MCP tool inventory

How these numbers stay true