The Machine Legibility Index measures a site across four pillars. Each guide takes one criterion from spec to verification. Identity comes first — when agents can't say who an organization is, whether a community legal aid clinic or a regional law firm, the rest of the audit doesn't carry weight. Start with I1.

Identity

Who does the site say it is?

I1

Declare who you are in machine-readable form so agents read your story, not a lookalike's.

Read guide →
I2

Declare the correct schema.org service type so agents can tell 'free immigration legal aid' from 'immigration law firm,' or 'community clinic' from 'urgent care chain.'

Read guide →
I3
Source authority and credentials Coming soon

Signal credentials so agents can distinguish a licensed clinic from a notario, a certified contractor from an imitator.

Reachability

Can an agent fetch and parse the site?

R1
Agent contract Coming soon

Tell AI crawlers what they can fetch and on what terms, so the site shows up the way it's intended to.

R2

Put critical content directly in the HTML — hours, eligibility, offerings — so agents see it on first fetch, not after JavaScript renders.

Read guide →
R3
Multilingual reach Coming soon

Signal which languages the site serves so a noncitizen family or a multilingual customer reaches a page they can actually read.

Structure

Can an agent make sense of what's there?

S1
Page type and breadcrumb Coming soon

Declare what kind of page this is — service page, application form, donation page, product page — so agents understand its role in the site.

S2
Heading hierarchy Coming soon

Structure headings so agents can outline your content accurately.

S3
Semantic density Coming soon

Use semantic HTML — buttons that are buttons, lists that are lists — so agents extract meaning, not just text.

Currency

Are the site's claims still true?

C1
Machine-readable dates Coming soon

Publish dates in a format machines can parse so "updated" means something agents can rank by.

C2
Time-sensitive markup Coming soon

Flag content that expires — clinic hours that changed last week, a promotion that ended Sunday — so agents don't surface stale information.

C3
Eligibility, cost, and availability Coming soon

Declare the details people in crisis need — hours, cost, who qualifies.

Implementation patterns

Cross-cutting guides that build on the pillars above — for teams scaling beyond a single page or site.

Iden

How to declare structured data once per page, consistently, when content is composed from many components and data sources. Extends I1 with a consolidation pattern, builder helpers, and anti-patterns to avoid.

Read guide →