# Lynk docs ## lynk Docs - [Overview](https://docs.getlynk.ai/readme.md): Lynk is a semantic layer for AI — a brain organized by concept that teaches an agent how your business thinks. - [Overview](https://docs.getlynk.ai/concepts/concepts.md): The router — every page in these docs and what it answers. Ground vocabulary here, then read the narrowest page. - [Project](https://docs.getlynk.ai/concepts/project.md): A Lynk project is a self-contained git repository — one repo, one customer — consumed as versioned, validated builds. - [lynk.yml](https://docs.getlynk.ai/concepts/lynk-yml.md): The required project settings file at the .lynk/ root — schema\_version, topology, and name. - [LYNK.md](https://docs.getlynk.ai/concepts/lynk-md.md): LYNK.md is the agent's orientation and identity — who the business is, who a team is, and how they think. Always loaded. - [GLOSSARY.yml](https://docs.getlynk.ai/concepts/glossary.md): GLOSSARY.yml is the team's vocabulary — the terms they use and what they mean, always loaded and merged across scopes. - [Domain](https://docs.getlynk.ai/concepts/domain.md): A domain is an agent — one team's analytical surface, with its own vocabulary, entities, skills, and policies. A user talks to one at a time. - [LYNK.md (domain)](https://docs.getlynk.ai/concepts/domain/lynk-md.md): A domain's LYNK.md — who this team is. Appended to the root LYNK.md; extends it, never replaces it. - [GLOSSARY.yml (domain)](https://docs.getlynk.ai/concepts/domain/glossary.md): A domain's GLOSSARY.yml — the team's vocabulary, merged over the root glossary with the domain winning on a key collision. - [Entity](https://docs.getlynk.ai/concepts/entity.md): An entity is a lazy, encapsulated representation of a thing in the business — a folder holding an ENTITY.md prose file and a schema.yml definition. - [ENTITY.md](https://docs.getlynk.ai/concepts/entity/entity-md.md): ENTITY.md is the prose side of an entity — quirks, conventions, and business context the agent reads. Short by design, frontmatter required. - [schema.yml](https://docs.getlynk.ai/concepts/entity/schema-yml.md): schema.yml is the structured definition of an entity — identity, keys, imports, features, metrics, and relationships. - [Identity and Imports](https://docs.getlynk.ai/concepts/entity/schema-yml/identity-and-imports.md): identity roots an entity in a warehouse table or view, or another entity; keys identify its rows; imports cherry-pick definitions from a parent entity. - [Feature](https://docs.getlynk.ai/concepts/entity/schema-yml/feature.md): A feature is a queryable, row-grain attribute of an entity — a column, a derivation, or a value pulled across a relationship. - [Metric](https://docs.getlynk.ai/concepts/entity/schema-yml/metric.md): A metric is an aggregation defined on the entity it aggregates — sum, count, average, conditional aggregates — invoked with metric(). - [Relationships](https://docs.getlynk.ai/concepts/entity/schema-yml/relationships.md): Relationships declare a path from an entity to a physical table or another entity — directional, per-step joins with cardinality. - [Policy](https://docs.getlynk.ai/concepts/policy.md): Policies are eager, always-apply behavioral commitments — output format, clarification behavior, and other rules for how the agent operates. - [Skill](https://docs.getlynk.ai/concepts/skill.md): Skills are lazy prose procedures for classes of analytical reasoning — how the agent thinks through an analysis, not what exists in the data. - [Reference Files](https://docs.getlynk.ai/concepts/reference-files.md): Reference files — user-organized files outside the domain primitives, the escape hatch for cross-cutting content, reached by absolute /.lynk/ references. - [Placing knowledge in a layer](https://docs.getlynk.ai/guides/where-knowledge-goes.md): How to decide where a piece of knowledge belongs — entity prose, schema, glossary, metric, skill, policy, LYNK.md, or a reference file. - [Choosing and shaping entities](https://docs.getlynk.ai/guides/designing-entities.md): How to decide what becomes an entity and how to shape it — the entity test, grain, promoting table relationships to entities, the upstream boundary, and base-row hygiene. Reach for it before adding or - [Modeling metrics, time, and state](https://docs.getlynk.ai/guides/metrics-time-and-state.md): How to place a computation — feature, metric, skill, or glossary term — and how to model balances, time windows, cohorts, and ratio KPIs correctly. - [Designing domains](https://docs.getlynk.ai/guides/designing-domains.md): How to decide how many domains to create, what belongs in the shared domain, and when to promote, extend, split, or merge. - [Budgeting the agent's context](https://docs.getlynk.ai/guides/context-engineering.md): How to budget the agent's context — deciding @ injection vs a link, splitting a growing ENTITY.md, placing content at root vs domain, and when a rule earns a policy. - [Evolving a live layer](https://docs.getlynk.ai/guides/evolving-the-layer.md): How to change a live semantic layer — logging definition changes, renaming a shared feature or metric safely, deprecating with enabled false, and landing breaking changes across domains. - [Reading a complete layer](https://docs.getlynk.ai/guides/complete-example.md): A complete, annotated .lynk/ project for Grove (B2B SaaS) — every file of a small correct layer, end to end, with the reasoning behind each choice. Read when you want the whole shape at once instead o - [Layout and Naming](https://docs.getlynk.ai/reference/layout-and-naming.md): The .lynk/ directory tree, the rules for naming folders and files, and the settings that control how a project is built. - [Markdown Format](https://docs.getlynk.ai/reference/markdown-format.md): The frontmatter contract shared by every Markdown primitive, the reference grammar (@ injection, markdown links, bare paths), and how supporting files are organized. - [SQL Expressions](https://docs.getlynk.ai/reference/sql-expressions.md): The reference grammar inside schema.yml sql fields — segment-count path resolution, the metric/first/last functions, filters, and join binding. - [What Lynk doesn't do](https://docs.getlynk.ai/reference/what-lynk-does-not-do.md): The boundaries in one place — testing and evaluations, metric parameterization, templating, tags, scheduling, cross-domain queries — what Lynk doesn't do by design, what's planned, and what belongs up - [API Reference](https://docs.getlynk.ai/api-reference/api.md): The programmatic interfaces — the Lynk SQL query dialect and the REST endpoints for validation and catalog inspection. - [Lynk SQL](https://docs.getlynk.ai/api-reference/api/lynk-sql.md): The query dialect — warehouse SQL plus metric(\.\) and USING('\'); entity references, joins, CTEs, windows, supported statements, pitfalls. - [REST API](https://docs.getlynk.ai/api-reference/api/rest-api.md): HTTP endpoints for validating the semantic layer and inspecting the data catalog — full documentation in progress. --- # Agent Instructions This documentation is published with GitBook. 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