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Execution module

As explained in AI Agents in Action, Second Edition

An execution module is an agent component that carries out selected operations through available actions or external tools.

An execution module carries out the current plan step by calling available tools, then writes the result back to a shared workspace. Like a ReAct agent, it acts on a sub-goal; unlike a bare tool call, it records evidence for later evaluation. section 10.2.5 section 10.2.1

Treat the module as a small, inspectable pipeline:

  • Read the current plan step or sub-goal from the workspace. section 10.2.5
  • Call a suitable tool through an MCP server or internal function. section 10.2.5
  • Wrap the raw result as a finding containing content, source, relevance score, and quality note. section 10.2.5
  • Return the finding to the workspace so the evaluation module can judge progress and confidence. section 10.2.5 section 10.2.1

Testing competing troubleshooting hypotheses

A plan asks the executor to investigate connection-pool exhaustion. It searches documentation, returns a relevance score of 0.8 with a quality note identifying official, directly relevant content, and lets evaluation increase confidence. A weaker community-blog result receives a 0.5 score and a partial-relevance note. section 10.3.3

Listing 10.4 04_execution_module.py
from agents import Agent, function_tool
from agents.mcp import MCPServerStdio

# Connect to domain-specific tools via MCP
search_server = MCPServerStdio(
    command="npx",
    args=["-y", "@modelcontextprotocol/server-filesystem", "./docs"]  #1
)

execution_agent = Agent(
    name="Executor",
    instructions="""You are the execution module of a cognitive agent.
    You receive a specific sub-goal from the current plan and execute
    it using available tools.

    For each result, provide:
    - content: The relevant information you found
    - source: Where it came from
    - relevance_score: 0.0 to 1.0, how relevant to the sub-goal
    - quality_note: Any concerns about the result quality
      (e.g., "source is a table of contents, not actual content",
       "result is partial", "high confidence match")

    Be honest about quality. A retrieval that returns metadata
    instead of content should get a low relevance_score and a
    quality_note explaining why.""",
    mcp_servers=[search_server],
    output_type=Finding,
)

Inspect a minimal filesystem-search implementation using an MCP server and an execution agent instructed to emit structured findings. section 10.2.5

How AI Agents in Action, Second Edition covers it

How deep it goes
Defines tool execution, result annotation, and evaluation feedback, then demonstrates search without detailing broader implementation internals.
Examples
Demonstrates filesystem search and troubleshooting hypothesis tests with relevance scores and quality notes.
What it assumes
Assumes a plan, shared workspace, and available tools while positioning execution alongside planning and evaluation.
What you can do after
Build it with MCP servers or function calls, return annotated findings, and expose weak results for evaluation.
How it connects
Connects planning modules, evaluation modules, shared workspaces, MCP servers, function calls, and cognitive-agent loops.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of AI Agents in Action, Second Edition. The section links point to the parts of the book it draws on.