Token Lens
Measure how much of the model context window your agent session is consuming before you trim, summarize, or swap models.
Overview
Token Lens is an MCP server for the Build phase that analyzes context-window token usage and helps you manage agent session budgets.
What is this MCP server?
- Analyzes context-window token usage for agent conversations
- Supports budget planning so you do not silently truncate mid-task
- Ships as npm package token-lens-mcp v0.1.2 over stdio MCP
- Pairs with any BYO LLM stack in Claude Code, Cursor, or Codex
- Lightweight stdio server—no hosted dependency in server.json
- Published version 0.1.2 on npm as token-lens-mcp
- Transport: stdio MCP per server.schema.json
- Source repository: github.com/mdfifty50-boop/token-lens-mcp
What problem does it solve?
Long agent sessions fill the context window without clear feedback, so tasks fail or degrade halfway through a solo build.
Who is it for?
Solo builders running multi-file agent sessions who want MCP-native visibility into context usage before trimming or switching models.
Skip if: Teams that only need provider billing dashboards and never debug in-IDE agent context limits.
What do I get? / Deliverables
After registering Token Lens, your agent can inspect token pressure and adjust prompts, summaries, or scope before context is exhausted.
- Registered stdio MCP server for token and context analysis
- Actionable view of context-window pressure during agent runs
- Clearer decisions on summarization, trimming, or model choice
Recommended MCP Servers
Journey fit
Token budgeting is a day-to-day constraint while wiring agents and long coding sessions, which is core Build-phase agent tooling. Fits agent-tooling because it instruments the LLM context layer your MCP client uses, not shipping gates or growth loops.
How it compares
MCP telemetry for context budgets, not a general code linter or hosted observability suite.
Common Questions / FAQ
Who is Token Lens for?
Indie and solo builders using MCP-enabled coding agents who need to see how full their context window is during real implementation work.
When should I use Token Lens?
Use it when sessions include big repos, long plans, or repeated tool output and you want to avoid truncation before shipping a feature.
How do I add Token Lens to my agent?
Install the npm package token-lens-mcp (v0.1.2), add a stdio MCP server entry pointing at that binary, and restart Claude Code, Cursor, or your MCP client.