@mcp-utils/retry

Implements automatic retry logic with exponential backoff for MCP (Model Context Protocol) tool handlers, allowing failed operations to be retried with progressively increasing delays between attempts. The capability wraps tool handler functions and intercepts errors, applying configurable backoff strategies (exponential, linear, or custom) before re-executing the handler. Built on the vurb library, it integrates directly into MCP server tool definitions without requiring changes to handler signatures.

Provides pluggable backoff strategies (exponential, linear, custom) that determine delay intervals between retry attempts. The capability allows developers to specify backoff parameters like initial delay, multiplier, and maximum delay cap, enabling tuning for different failure scenarios (e.g., exponential for rate limits, linear for transient network glitches). Strategies are applied deterministically without jitter by default, with optional randomization support.

Enforces a configurable maximum number of retry attempts, after which the original error is propagated to the caller. The capability tracks attempt count across retries and terminates the retry loop when the limit is reached, preventing infinite retry cycles. Developers can configure per-handler attempt limits (e.g., 3 attempts, 5 attempts) and receive the final error with full context about how many retries were attempted.

Intercepts errors thrown by MCP tool handlers and applies retry logic before propagating failures. The capability wraps handler execution in a try-catch boundary, captures error context (error type, message, stack), and decides whether to retry or fail immediately. Errors are preserved through the retry chain and returned with full context when retries are exhausted, maintaining error semantics for MCP client error handling.

Leverages the vurb library as the underlying retry engine, providing a lightweight, composable abstraction for retry orchestration. Vurb handles the core retry loop, backoff calculation, and attempt tracking, while @mcp-utils/retry adds MCP-specific integration. This design separates concerns: vurb manages retry mechanics, while the wrapper handles MCP tool handler adaptation and configuration.