Your MCP Server is Bad (and you should feel bad) - Jeremiah Lowin, Prefect

Discovery is prohibitively expensive

Unlike humans who study documentation once, agents must rediscover the entire server on every activation, burning tokens to enumerate every tool and description.

Iteration is the enemy

While humans iterate code rapidly, each additional agent tool call transmits the full conversation history over the wire, making multi-step workflows slow and costly.

Context windows are severely constrained

Agents operate with limited memory (around 200k tokens) compared to human long-term memory, requiring interfaces that minimize cognitive load and decision points.

Atomic operations are an anti-pattern

Exposing granular functions like get_user and filter_orders forces agents into expensive orchestration instead of single-call solutions that return complete outcomes.

Agents make terrible glue code

Using LLMs to chain atomic operations is slow, stochastic, and hard to debug compared to deterministic orchestration tools like Prefect or Airflow.

Design for agent stories

Tools should represent complete workflows (e.g., 'track latest order by email') rather than steps that require agent reasoning to sequence and execute.

Raw API wrappers fail agents

Simply stringifying REST API responses creates 'needles in haystacks' where agents must examine every field to find relevant data, consuming excessive context.

Agents deserve purpose-built interfaces

Just as humans use websites and apps instead of raw APIs, agents need interfaces curated specifically for their strengths and weaknesses, not repurposed human developer tools.

Curate ruthlessly to minimize discovery

Every exposed tool and description adds to the discovery tax, so servers must eliminate unnecessary surface area and optimize for the agent's limited context window.