declarative-agents vs harness-sdk
Agent development frameworks compared
declarative-agents runs tool-augmented agents from YAML profiles in a shared Go runtime, while harness-sdk provides Python and TypeScript harnesses and SDKs. The main difference is configuration-defined workflows versus a harness and SDK approach that lets teams configure or control the agent loop directly.
declarative-agents: Define Tool-Augmented Agents in YAML
A Go runtime interprets YAML profiles that define agent tools, states, transitions, and budgets. It suits teams that want to change agent workflows through configuration, though the project is new, contributor-concentrated, and in bug-fix-only maintenance mode.
harness-sdk: Build and Run AI Agents in Python and TypeScript
Strands Agents provides Python and TypeScript tools for building AI agents, from a ready-made harness to a customizable agent SDK. It suits teams that want model flexibility and control over agent execution without a hosted control plane.
| declarative-agents | harness-sdk | |
|---|---|---|
| Language | Go | Python |
| License | BSD-3-Clause | Apache-2.0 |
| Stars | 4 | 8.6k |
| Forks | 1 | 1.3k |
| Last analyzed | Oct 11, 2026 | Oct 3, 2026 |
Key differences
- declarative-agents defines agent states, transitions, tools, and budgets in YAML profiles; harness-sdk offers configurable harnesses and lower-level SDKs for agent setup and execution.
- declarative-agents is written in Go; harness-sdk supports Python and TypeScript.
- declarative-agents includes reusable agent and tool blocks, application compositions, a DSL specification, and design-pattern guidance; harness-sdk includes provider integrations, MCP, lifecycle controls, tracing, guardrails, and evaluation support.
- declarative-agents is licensed under BSD-3-Clause; harness-sdk is licensed under Apache-2.0.
- declarative-agents is in maintenance mode and accepts bug fixes only; harness-sdk reports 938 open issues.
- declarative-agents has 4 stars and 1 fork; harness-sdk has 8.6k stars and 1.3k forks.
Choose declarative-agents if you…
- want to change agent workflows through YAML profiles without changing the runtime binary.
- need reusable agent and tool blocks or example application compositions to build from.
- want to study a documented DSL and design patterns for declarative agent workflows.
Choose harness-sdk if you…
- need a ready-made Python or TypeScript harness, or lower-level SDKs for more control.
- want to choose among documented model providers and connect tools, including through MCP.
- need execution limits, hooks, tracing, guardrails, or evaluation support for agent applications.
Compare the numbers side by side, or add more projects
This comparison is generated with AI from the OSRepos analyses of both projects. Always check each project's repository and documentation before choosing.