Add agent fundamentals documentation for issue #367

[vinod151019]

Adds a new 'What is an Agent?' page as the overview/landing page for the Agents section in the User Guide. This addresses confusion about:

• What an agent actually represents in Strands
• The four parts of an agent (Model, System Prompt, Tools, Context)
• Agent lifecycle and scope (one agent per conversation)
• Anti-patterns: sharing agents across users or conversations

Closes strands-agents/harness-sdk#2578

Description

New page: src/content/docs/user-guide/concepts/agents/what-is-an-agent.mdx
Updated: src/config/navigation.yml to add the page as first item under Concepts → Agents

Related Issues

Closes strands-agents/harness-sdk#2578

Type of Change

• New content

Checklist

• I have read the CONTRIBUTING document
• My changes follow the project's documentation style
• I have tested the documentation locally using npm run dev
• Links in the documentation are valid and working

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By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[vinod151019]

Hi @zastrowm! Pushed a new commit (37a59bf) to fix the CI build. Updated the page to follow the repo's existing MDX conventions:

• Moved the TypeScript examples into a sibling what-is-an-agent.ts and included them via --8<-- snippet markers (matches prompts.ts, state.ts, agent-loop.ts)
• Removed the unimported / JSX that was breaking the MDX build
• Fixed internal link extensions to use .md to match the rest of the docs

Verified locally: npm run build (443 pages, no broken links), npm run typecheck, npm run typecheck:snippets, and npm test (291 passed) all clean.

All content from issue strands-agents/harness-sdk#2578 is preserved four parts (Model, System Prompt, Tools, Context), lifecycle/scope discussion, and the three anti-patterns (shared singleton, reused across conversations, cached per user).

[strands-agent]

This repository has been merged into the strands-agents/harness-sdk monorepo and will be archived shortly. All new development happens there.

If this PR is still relevant, please recreate it against the monorepo. The code now lives under site/. Full commit history was preserved, so your base should be findable.

Apologies for the disruption, and thank you for contributing!