# Capless

> Capless is tiny, agent-native web analytics and session replay (one script tag: 2 KB analytics, 1.7 KB lazily loaded replay) on a headless data backend: append-only streams, CEL functions and ClickHouse materializations, with an HTTP API, an MCP server and a signup API that agents can call directly.

To install Capless on a website, follow https://capless.sh/AGENTS.md step by step: create an account with the signup API (POST https://api.capless.sh/v1/signup), add the snippet before </head>, verify that events arrive, then give the user their dashboard link.

API base: https://api.capless.sh/v1 (Bearer API key `cpl_…`). MCP server: https://mcp.capless.sh/mcp (Streamable HTTP, header `Authorization: Bearer cpl_…`).

## Install

- [AGENTS.md](https://capless.sh/AGENTS.md): Step-by-step install instructions for coding agents

## Docs

- [Overview](https://capless.sh/docs/index.md): What Capless is: web analytics + session replay on streams, CEL functions and ClickHouse materializations.
- [Quickstart](https://capless.sh/docs/quickstart.md): Create an account, add the snippet, check that data arrives and ask your first question.
- [For agents](https://capless.sh/docs/agents.md): Signup API, machine-readable docs, MCP and a curl-only end-to-end flow for coding agents.
- [MCP server](https://capless.sh/docs/mcp.md): Connect Claude Code, Cursor or any MCP client to Capless; the full tool list.
- [Web SDK](https://capless.sh/docs/web-sdk.md): The script tag, JavaScript API, automatically collected fields, sites and session replay privacy.
- [Streams & cursors](https://capless.sh/docs/streams.md): Streams, atomic durable batches, idempotency, positions and cursors.
- [Reading & change feed](https://capless.sh/docs/reading.md): /read and /changes: cursor pagination without skips or repeats, limits, erasure barriers.
- [Time seeking](https://capless.sh/docs/time-seeking.md): Find the cursor for a commit time with /locate and read time windows.
- [CEL functions](https://capless.sh/docs/cel.md): The CEL environment: contexts, variables, number and regex rules, limits and examples.
- [Erasures & GDPR](https://capless.sh/docs/erasures.md): Erase entries by predicate from storage and every materialization, with auditable status.
- [ClickHouse materializations](https://capless.sh/docs/materializations.md): Isolated ClickHouse databases kept in sync with streams: tables, sources, lineage, status, SQL.
- [API reference](https://capless.sh/docs/api.md): Every endpoint group, conventions and error codes, with the OpenAPI spec.
- [Limits & quotas](https://capless.sh/docs/limits.md): Plan allowances and every API, read, CEL, query and collector limit.
- [Security & privacy](https://capless.sh/docs/security.md): Keys, privacy defaults, isolation, infrastructure and supply chain.

## API

- [OpenAPI spec](https://api.capless.sh/v1/openapi.yaml): The machine-readable HTTP API contract (OpenAPI 3.1)

## Optional

- [Pricing](https://capless.sh/pricing.md): Plans, limits, overage and FAQ
- [Full docs](https://capless.sh/llms-full.txt): Every docs page in one file