fix(sdk/subagent): fix get_factory_info()

[VascoSch92]

Summary

This fixes get_factory_info() so the default agent's description is defined in one place (its frontmatter) rather than being duplicated as a special case in the registry code.

• Remove the hardcoded "default" agent entry from get_factory_info() output, so it only lists user-registered agents
• Move the "used when no agent type is provided" description into the actual default agent definition files (default.md, default_cli.md) where it belongs
• Simplify early return when no user agents are registered

Note

This is a beaviouhr change but it is not a problem as we give the default agent to the DelegateTool always, i.e., there is no change in this sense.

Checklist

• If the PR is changing/adding functionality, are there tests to reflect this?
• If there is an example, have you run the example to make sure that it works?
• If there are instructions on how to run the code, have you followed the instructions and made sure that it works?
• If the feature is significant enough to require documentation, is there a PR open on the OpenHands/docs repository with the same branch name?
• Is the github CI passing?

---

Agent Server images for this PR

• GHCR package: https://github.com/OpenHands/agent-sdk/pkgs/container/agent-server

Variants & Base Images

Variant	Architectures	Base Image	Docs / Tags
java	amd64, arm64	eclipse-temurin:17-jdk	Link
python	amd64, arm64	nikolaik/python-nodejs:python3.12-nodejs22	Link
golang	amd64, arm64	golang:1.21-bookworm	Link

Pull (multi-arch manifest)

# Each variant is a multi-arch manifest supporting both amd64 and arm64
docker pull ghcr.io/openhands/agent-server:7d01015-python

Run

docker run -it --rm \
  -p 8000:8000 \
  --name agent-server-7d01015-python \
  ghcr.io/openhands/agent-server:7d01015-python

All tags pushed for this build

ghcr.io/openhands/agent-server:7d01015-golang-amd64
ghcr.io/openhands/agent-server:7d01015-golang_tag_1.21-bookworm-amd64
ghcr.io/openhands/agent-server:7d01015-golang-arm64
ghcr.io/openhands/agent-server:7d01015-golang_tag_1.21-bookworm-arm64
ghcr.io/openhands/agent-server:7d01015-java-amd64
ghcr.io/openhands/agent-server:7d01015-eclipse-temurin_tag_17-jdk-amd64
ghcr.io/openhands/agent-server:7d01015-java-arm64
ghcr.io/openhands/agent-server:7d01015-eclipse-temurin_tag_17-jdk-arm64
ghcr.io/openhands/agent-server:7d01015-python-amd64
ghcr.io/openhands/agent-server:7d01015-nikolaik_s_python-nodejs_tag_python3.12-nodejs22-amd64
ghcr.io/openhands/agent-server:7d01015-python-arm64
ghcr.io/openhands/agent-server:7d01015-nikolaik_s_python-nodejs_tag_python3.12-nodejs22-arm64
ghcr.io/openhands/agent-server:7d01015-golang
ghcr.io/openhands/agent-server:7d01015-java
ghcr.io/openhands/agent-server:7d01015-python

About Multi-Architecture Support

• Each variant tag (e.g., 7d01015-python) is a multi-arch manifest supporting both amd64 and arm64
• Docker automatically pulls the correct architecture for your platform
• Individual architecture tags (e.g., 7d01015-python-amd64) are also available if needed

[github-actions]

API breakage checks (Griffe)

Result: Failed

Log excerpt (first 1000 characters)

============================================================
Checking openhands-sdk (openhands.sdk)
============================================================
Comparing openhands-sdk 1.11.5 against 1.11.4
::notice title=openhands-sdk API::Ignoring Field metadata-only change (non-breaking): load_public_skills
::notice title=openhands-sdk API::Ignoring Field metadata-only change (non-breaking): temperature
::warning file=openhands-sdk/openhands/sdk/llm/llm.py,line=196,title=LLM.top_p::Attribute value was changed: `Field(default=1.0, ge=0, le=1)` -> `Field(default=None, ge=0, le=1, description='Nucleus sampling parameter. Defaults to None (uses provider default). Set to a value between 0 and 1 to control diversity of outputs.')`
::error title=SemVer::Breaking changes detected (1); require at least minor version bump from 1.11.x, but new is 1.11.5

============================================================
Checking openhands-workspace (openhands.workspace)
============================

Action log

[github-actions]

Agent server REST API breakage checks (OpenAPI)

Result: Passed

Action log

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
openhands-sdk/openhands/sdk/subagent
registry.py	94	6	93%	76, 154–155, 159, 197–198
TOTAL	19600	6071	69%

[VascoSch92]

Recommendation: This should be reviewed by a maintainer and ideally verified with lightweight evals before merging to ensure the behavior change does not affect agent decision-making or benchmark performance.

This is pretty nice :-)

[all-hands-bot]

Taste Rating: 🟡 Acceptable - Eliminates duplication but changes public API behavior

Assessment: This simplifies the code by moving the default agent description to its definition file (good taste - eliminates special case). However, this is a breaking change to get_factory_info()s public API output, which affects tool descriptions.

Key Concern: This PR changes how tools present agent information to LLMs. According to repo policy, changes that "could plausibly affect benchmark/evaluation performance" (including tool calling/execution) should not be approved without human review and lightweight evals.

Verdict: ⚠️ Needs human maintainer review - core refactor is sound, but tool behavior change requires eval verification before merge.