--- title: How do I build my own agent? — The Agentic AI Hub | daily.dev description: What an agent actually is, harnesses vs frameworks, tools via MCP, and the context and verification that keep it honest. canonical: https://daily.dev/agentic-ai-hub/paths/build-your-own-agent/ og:type: website og:url: https://daily.dev/agentic-ai-hub/paths/build-your-own-agent/ og:title: How do I build my own agent? — The Agentic AI Hub | daily.dev og:description: What an agent actually is, harnesses vs frameworks, tools via MCP, and the context and verification that keep it honest. og:image: https://daily.dev/assets/og/agentic-ai-hub.png?v=40e6ff69 og:site_name: daily.dev og:locale: en_US twitter:card: summary_large_image twitter:site: @dailydotdev twitter:creator: @dailydotdev twitter:title: How do I build my own agent? — The Agentic AI Hub | daily.dev twitter:description: What an agent actually is, harnesses vs frameworks, tools via MCP, and the context and verification that keep it honest. twitter:image: https://daily.dev/assets/og/agentic-ai-hub.png?v=40e6ff69 --- [Skip to main content ](#main-content) # How do I build my own agent? What an agent actually is, harnesses vs frameworks, tools via MCP, and the context and verification that keep it honest. [Start reading → ](/agentic-ai-hub/agentic-engineering-core-ideas/?path=build-your-own-agent&i=0#what-an-agent-actually-is) [Check yourself first ↓ ](#quiz) 1. [ 1 What an agent actually is In Agentic Engineering: Core Ideas "Agentic coding" is an overloaded term. › ](/agentic-ai-hub/agentic-engineering-core-ideas/?path=build-your-own-agent&i=0#what-an-agent-actually-is) 2. [ 2 Agent Harnesses & Frameworks Two very different things get called "agent tooling." › ](/agentic-ai-hub/agent-harnesses-frameworks/?path=build-your-own-agent&i=1) 3. [ 3 MCP & the Tool/Context Ecosystem Models are only half the story. The other half is the plumbing that gives models hands: how an assistant reaches your files, databases, SaaS tools, and the web. › ](/agentic-ai-hub/mcp-tool-context-ecosystem/?path=build-your-own-agent&i=2) 4. [ 4 Context, Skills & Memory Agents are only as good as what they know when they start, and by default they start knowing nothing about your repo, your conventions, or last week's decisions. › ](/agentic-ai-hub/context-skills-memory/?path=build-your-own-agent&i=3) 5. [ 5 Verification & Testing for Agents If generation is cheap and verification is the bottleneck, then verification infrastructure is your leverage. › ](/agentic-ai-hub/verification-testing-for-agents/?path=build-your-own-agent&i=4) 6. [ 6 When one agent isn't enough Once one agent works, the obvious move is to run several. This is where the biggest gains and the biggest self-inflicted wounds both live. › ](/agentic-ai-hub/orchestration-patterns/?path=build-your-own-agent&i=5) ## Check yourself. One question per step. Take it cold to find where to start, or after reading to see what stuck. Nobody's grading you. Best so far: Question 1 of 6 1. Step 1 In the now-settled definition, what makes a system an agent rather than a workflow? A It coordinates multiple specialized models B The model directs its own process and tool use C It maintains memory across sessions D It runs fully autonomously without human review An agent is an LLM running tools in a loop toward a goal, directing its own process; a workflow runs LLMs through predefined code paths. Anthropic's advice is to prefer the simpler workflow until agency demonstrably improves outcomes. [Covered in step 1 · What an agent actually is → ](/agentic-ai-hub/agentic-engineering-core-ideas/?path=build-your-own-agent&i=0#what-an-agent-actually-is) Next question → 2. Step 2 When does an agent framework beat a plain provider SDK plus a loop? A For any production agent, since frameworks are battle-tested B Once your agent uses more than a handful of tools C When you want the model to reason more reliably D When you need durable state, multi-agent coordination, or checkpoints For a single agent with a few tools, an SDK plus a loop is often simpler and more debuggable. Frameworks earn their keep on orchestration you'd otherwise reinvent, like durable state, multi-agent coordination, and human-in-the-loop checkpoints. [Covered in step 2 · Agent Harnesses & Frameworks → ](/agentic-ai-hub/agent-harnesses-frameworks/?path=build-your-own-agent&i=1) Next question → 3. Step 3 How does MCP relate to the function calling that model APIs already provide? A It sits above it, standardizing how tools are described and shared B It replaces function calling with a new mechanism C It executes tools directly, bypassing the model D It only standardizes Anthropic's tool-call format MCP tools reach the model through the same tool-calling mechanism every frontier API exposes; what MCP standardizes is where the functions come from and how they're described, so one server works across providers and apps. [Covered in step 3 · MCP & the Tool/Context Ecosystem → ](/agentic-ai-hub/mcp-tool-context-ecosystem/?path=build-your-own-agent&i=2) Next question → 4. Step 4 Why is "give the agent as much context as possible" bad advice? A Long prompts cost more than they're worth B Models reject inputs near the context limit C Recall degrades as context grows, well before the hard limit D Extra context slows generation to a crawl The chapter documents "context rot": as tokens in the window increase, the model's ability to accurately recall from context decreases, and failure modes like poisoning, distraction, and clash appear long before you hit the limit. [Covered in step 4 · Context, Skills & Memory → ](/agentic-ai-hub/context-skills-memory/?path=build-your-own-agent&i=3) Next question → 5. Step 5 You wire your test suite into an agent's loop. Why must the tests be protected from the implementer? A An agent optimizing for green will edit or delete failing tests B Agents misread test output without special formatting C Test files crowd the code out of context D Running tests every iteration is too slow Kent Beck reports having trouble stopping agents from deleting tests to make them "pass". The guardrail is also a target, so tests should be owned by the checker role or locked against implementer edits. [Covered in step 5 · Verification & Testing for Agents → ](/agentic-ai-hub/verification-testing-for-agents/?path=build-your-own-agent&i=4) Next question → 6. Step 6 You're splitting a feature across parallel agents. Which work actually parallelizes well? A Implementation, since code writing benefits most from parallelism B Any work, once each agent has its own worktree C Read-style work like research and review; shared-codebase writes don't D Only tasks small enough to fit one context window The cleanest rule in the multi-agent debate is that read actions are inherently more parallelizable than writes: research and review fan out, while merging conflicting writes (and the conflicting assumptions behind them) is the expensive part. [Covered in step 6 · When one agent isn't enough → ](/agentic-ai-hub/orchestration-patterns/?path=build-your-own-agent&i=5) See results → of 6 * [ 1 What an agent actually is → ](/agentic-ai-hub/agentic-engineering-core-ideas/?path=build-your-own-agent&i=0#what-an-agent-actually-is) * [ 2 Agent Harnesses & Frameworks → ](/agentic-ai-hub/agent-harnesses-frameworks/?path=build-your-own-agent&i=1) * [ 3 MCP & the Tool/Context Ecosystem → ](/agentic-ai-hub/mcp-tool-context-ecosystem/?path=build-your-own-agent&i=2) * [ 4 Context, Skills & Memory → ](/agentic-ai-hub/context-skills-memory/?path=build-your-own-agent&i=3) * [ 5 Verification & Testing for Agents → ](/agentic-ai-hub/verification-testing-for-agents/?path=build-your-own-agent&i=4) * [ 6 When one agent isn't enough → ](/agentic-ai-hub/orchestration-patterns/?path=build-your-own-agent&i=5) Try again [Where to next → ](#path-next-title) ## Where to next. More guided paths through the handbook. Pick the next question worth answering. [ Can I trust what agents produce? → ](/agentic-ai-hub/paths/trust-agent-output/)[ How do I ground AI in my company's data? → ](/agentic-ai-hub/paths/ground-in-your-data/)[ How do I ship an AI feature to production? → ](/agentic-ai-hub/paths/ship-to-production/) [All reading paths → ](/agentic-ai-hub/#paths-start-here) [Browse every chapter ](/agentic-ai-hub/#pages) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/og-image.png?v=a830cdf1","width":1200,"height":630},"sameAs":["https://twitter.com/dailydotdev","https://www.linkedin.com/company/dailydotdev","https://github.com/dailydotdev","https://www.instagram.com/dailydotdev"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","description":"Free, personalized developer news aggregator. 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