mcp tool wrapping with transparent metering instrumentation
Wraps arbitrary MCP server tools with metering middleware that intercepts tool invocations without modifying the underlying tool logic. Uses a decorator/proxy pattern to inject usage tracking at the MCP protocol boundary, capturing invocation metadata (tool name, input size, execution time, output tokens) before passing through to the original tool handler. Maintains full MCP protocol compatibility while adding observability hooks for billing calculations.
Unique: Implements MCP-native metering via protocol-level wrapping rather than application-level logging, allowing transparent instrumentation of any MCP tool without code changes to the tool itself. Uses MCP's built-in request/response cycle to capture metrics at the protocol boundary.
vs alternatives: Simpler than building custom billing logic into each tool and more MCP-native than generic HTTP request logging, since it understands MCP tool schemas and can extract semantic usage signals (tool name, parameter types) directly from protocol messages.
usage metric extraction and aggregation from tool invocations
Automatically extracts structured usage metrics from each MCP tool invocation, including execution duration, input/output token counts (if applicable), tool name, and invocation timestamp. Aggregates metrics across multiple invocations into usage events that can be exported for billing. Supports custom metric extractors for tool-specific billing dimensions (e.g., API calls made by a tool, database queries executed).
Unique: Extracts metrics at the MCP protocol level, allowing it to understand tool semantics (tool name, schema) and capture usage signals that generic HTTP/RPC logging cannot. Supports pluggable metric extractors for domain-specific billing dimensions without modifying core metering logic.
vs alternatives: More semantic than generic request logging (which only sees bytes/latency) because it understands MCP tool schemas and can extract tool-specific billing signals; more flexible than hardcoded billing logic because extractors are composable and reusable.
billing event generation and export for downstream processors
Converts metered usage data into billing-ready events that can be exported to external billing systems (Stripe, custom databases, data warehouses). Generates structured billing events with tool usage, metrics, timestamps, and optional customer/tenant identifiers. Supports batch export and streaming event emission for real-time billing pipelines. Events are formatted as JSON and can be written to files, HTTP endpoints, or message queues.
Unique: Generates billing events directly from MCP protocol-level metrics, avoiding the need to instrument billing logic in individual tools or applications. Events are MCP-aware (include tool schema info, protocol metadata) and can be exported to multiple destinations in parallel.
vs alternatives: More integrated than generic usage logging because it understands MCP tool semantics and can generate billing events with tool-specific context; more flexible than hardcoded billing because export destinations and event schemas are configurable.
multi-tenant usage isolation and attribution
Provides mechanisms to tag and isolate usage metrics by tenant, customer, or API key, enabling accurate cost attribution in multi-tenant MCP deployments. Supports tenant context propagation through MCP request metadata or custom headers, ensuring each tool invocation is attributed to the correct billing entity. Enables per-tenant usage reports and cost breakdowns without cross-contamination of metrics.
Unique: Implements tenant isolation at the MCP middleware layer, allowing usage to be tagged and segregated without modifying individual tools or requiring tenant-aware tool implementations. Supports multiple tenant context sources (headers, metadata, custom fields) for flexibility in different deployment architectures.
vs alternatives: Simpler than implementing tenant isolation in each tool because it's centralized in the metering middleware; more flexible than hardcoded tenant detection because context sources are pluggable and configurable.
custom metric extractor plugin system
Provides a plugin interface for defining custom metric extractors that can capture tool-specific billing dimensions beyond standard execution time and token counts. Extractors are functions that receive the tool invocation request/response and can compute arbitrary metrics (e.g., number of database queries, external API calls, data volume processed). Extracted metrics are included in billing events and usage reports, enabling fine-grained cost attribution based on tool behavior.
Unique: Provides a composable plugin interface for metric extraction that runs at the MCP protocol boundary, allowing extractors to access both request and response data without modifying tool implementations. Extractors are decoupled from metering core, enabling independent development and reuse across tools.
vs alternatives: More flexible than hardcoded billing logic because extractors are pluggable and reusable; more semantic than generic logging because extractors understand tool-specific behavior and can compute domain-specific metrics.
usage-based rate limiting and quota enforcement
Enforces usage quotas and rate limits based on metered tool invocations, preventing over-consumption and enabling fair-use policies. Supports per-tenant quotas (e.g., max 1000 tool calls per month), per-tool rate limits (e.g., max 10 calls/second), and custom quota rules. Blocks or throttles tool invocations when quotas are exceeded, returning quota-exceeded errors to the caller. Quotas can be reset on configurable schedules (daily, monthly, etc.).
Unique: Implements quota enforcement at the MCP middleware layer, allowing quotas to be applied uniformly across all tools without modifying individual tool implementations. Supports multiple enforcement modes (blocking, throttling) and custom quota rules for flexible policy implementation.
vs alternatives: More integrated than external rate limiting (e.g., API gateway) because it understands MCP tool semantics and can enforce tool-specific quotas; more flexible than hardcoded limits because quotas are configurable and can be adjusted per tenant.