Crate llm_browser_testkit 

LLM-driven browser test framework.

Provides reusable building blocks for browser-based test scenarios:

• Browser client via Chrome DevTools Protocol (headless)
• LLM client for natural language element targeting and assertions
• A2A agent integration for agent-to-agent communication
• MCP client/server integration for tool-calling
• Cost tracking, token counting, and budget enforcement
• Declarative TOML scenario runner
• #[browser_test] macros for cargo test integration

Re-exports

pub use costs::LlmResponse;

pub use costs::LlmUsage;

pub use scenario::AuthConfig;

pub use scenario::AuthMode;

pub use scenario::AwsConfig;

pub use scenario::Provider;

Modules

a2a

A2A agent protocol client. A2A (Agent-to-Agent) protocol client.

budgets

Budget tracking and enforcement. Budget tracking and enforcement.

costs

Cost calculation, usage tracking, and pricing. Cost calculation, usage tracking, and pricing logic.

diagnostics

Failure diagnostics — page-state capture and artifact writing. Failure diagnostics — page-state capture and artifact writing.

endpoints

Endpoint registry and routing resolver. Endpoint registry — resolves named endpoints and task-type routing.

events

Typed run events emitted by the runner. Typed run events emitted by the runner.

mcp_client

MCP client for connecting to external MCP servers. MCP (Model Context Protocol) client.

mcp_server

MCP server for exposing the framework as an MCP server. MCP server exposure — exposes the framework as an MCP server.

redact

Secret redaction for every report sink. Secret redaction for every report sink.

reporting

Run reporting: console, NDJSON, JUnit, GitHub and Perfetto sinks. Report sinks: console, NDJSON, JUnit XML, GitHub annotations, Perfetto trace.

runner

Step-by-step scenario executor (navigate, click, type, wait, assert).

scenario

Declarative TOML-based test scenario types. Scenario types for human-readable browser test case definitions.

selectors

CSS selector sanitization for LLM-generated selectors. CSS selector sanitization and validation for LLM-generated selectors.

vision

Vision support — screenshot capture/downscale/encode for visual asserts. Vision support — screenshot capture, tiling, downscaling, and JPEG encoding for LLM visual assertions.

Structs

LlmConfig

Configuration for the LLM client — bundles URL, model, auth, timeouts, and provider-specific options into a single struct passed everywhere.

Constants

DEFAULT_AZURE_API_VERSION

Default Azure OpenAI API version used when an endpoint does not set api_version.

DOM_EXTRACT_JS

JavaScript to extract interactive elements from the current page. Returns a JSON array of objects with tag, selector, and label.

Functions

base_url

Returns the target base URL from HARNESS_BROWSER_BASE_URL env, defaulting to http://localhost:4200.

browser_headless

Returns whether to run the browser in headless mode from HARNESS_BROWSER_HEADLESS env, defaulting to true.

build_azure_url

Builds the Azure OpenAI chat completions URL: the resource endpoint (without /openai), the deployment name, and the API version.

default_llm_attempts

Reads HARNESS_LLM_CALL_ATTEMPTS (default 3) — how many times a single chat completion is retried before the endpoint is considered failed.

http_client

Builds a reqwest::Client with the given timeout.

llm_base_url

Returns the LLM server base URL from HARNESS_LLM_TEST_URL env, defaulting to http://localhost:8080.

llm_chat

Sends a chat completion request to the LLM.

llm_chat_vision_with_usage

Sends a vision-enabled chat completion request.

llm_chat_vision_with_usage_chain

Vision variant of llm_chat_with_usage_chain.

llm_chat_with_usage

Sends a chat completion request to the LLM and returns both the content and token usage from the API response.

llm_chat_with_usage_chain

Calls a chain of endpoints: the primary LlmConfig first, then each fallback in order. Every endpoint gets its own max_attempts retry budget; the first endpoint that answers wins.

llm_model

Returns the LLM model name from HARNESS_LLM_TEST_MODEL env, defaulting to deepseek.

parse_headers_env

Parses HARNESS_LLM_HEADERS env var (JSON object) into a header map.

truncate

Truncates a string to the given maximum length, appending a marker with the number of omitted characters if truncation occurred.