# Agent Skills official support — Harness vs Strands vs Quick

Sources checked **14 August 2026**:

- [AgentCore Harness skills](https://docs.aws.amazon.com/bedrock-agentcore/latest/devguide/harness-skills.html)
- [Strands AgentSkills plugin](https://strandsagents.com/docs/user-guide/concepts/plugins/skills/index.md)
- [AgentSkills.io specification](https://agentskills.io/specification)
- [Quick custom chat agents](https://docs.aws.amazon.com/quick/latest/userguide/custom-agents.html)
- [Quick Flows AI response steps](https://docs.aws.amazon.com/quick/latest/userguide/ai-response-steps.html)
- [AWS Agent Toolkit skills guide](https://www.factualminds.com/blog/aws-agent-toolkit-for-aws-skills-guide/)

## Official AgentSkills.io support

| Capability | Harness | Strands | Quick Chat Agents | Quick Flows | Quick Automate |
| --- | --- | --- | --- | --- | --- |
| AgentSkills.io `SKILL.md` | **Official** — `awsSkills`, Git, S3, path | **Official** — `AgentSkills` plugin, `Skill.from_file` / `from_url` / `from_directory` | No | No | No |
| AWS Agent Toolkit catalog | `awsSkills` glob (`core-skills/*`, ops, storage, analytics) | Load the same packs from disk or Git if you wire them | N/A | N/A | N/A |
| Progressive disclosure (~100 token metadata, full body on demand) | Yes | Yes | Instructions live in the persona | Step prompts | Process-doc → generated plan |
| Per-invoke skill override | Yes (`InvokeHarness` skills append; same name wins) | Code / plugin config change | No | No | No |
| Git pin (commit / branch) | Yes (HTTPS Git source) | Yes (you clone into the Runtime image or fetch) | No | No | No |
| Private Git via AgentCore Identity credential | Yes (`auth.credentialArn`) | DIY in the container | No | No | No |
| Closest Quick equivalent | — | — | Custom instructions + Spaces + action connectors + uploaded reference docs | Embed a chat agent as a **single-turn** step | Upload process docs → automation plan |

## What “official” means here

**Official** = the product documents Agent Skills as a first-class config or SDK plugin that loads `SKILL.md` bundles with progressive disclosure.

Quick Chat Agents, Flows, and Automate are **agentic**, but they do **not** implement the AgentSkills.io file format. Pasting a `SKILL.md` body into Quick instructions is a different artifact: no glob catalog, no per-invoke override, no ~100-token metadata injection.

## Harness skill sources (GA with Harness, 17 June 2026)

| Source | When to use |
| --- | --- |
| `awsSkills` | Ready-made AWS procedures; enable with glob paths |
| Git (HTTPS) | Public or private repo; subdirectory via sparse checkout |
| Amazon S3 | Customer-owned bucket; execution role; encryption / versioning you control |
| Path | Already on the harness filesystem (image or `InvokeAgentRuntime`) |

Skills fetch once per session on first invoke; a new session re-fetches. Git fetch must complete within 60 seconds (NAT if the harness is in a VPC).

## Opinionated rule

If the team already maintains `SKILL.md` packs, **do not “port skills” into Quick**. Point Harness at `awsSkills` / Git / S3, or load them with Strands `AgentSkills`. Use Quick for ACL-aware employee chat and no-code Flows — a different contract.