---

name: backends description: "Select hls4ml backends, generate backend configs, write or inspect projects, and parse build reports safely." disable-model-invocation: true metadata: disco-role: operating license: Apache 2.0

Backends

Use this sub-skill when the question is about backend selection, project layout, build/report invocation, report parsing, backend defaults, or vendor tool prerequisites.

Route here

• backend choice and default config values
• create_config(...) backend options and board/part/clock settings
• ModelGraph.write(), compile(), and build()
• legacy CLI build/report compatibility and deprecation notes
• report parsing for existing synthesis outputs

Route away

• model conversion and frontend parsing → frontends
• precision tuning, bit-exactness, FIFO sizing, or BramFactor strategy → analysis
• custom backend registration, plugins, or template authoring → extensions

Safe workflow

1. Inspect the installed backend registry with scripts/inspect_backends.py.
2. Confirm the legacy CLI surface with scripts/check_cli_help.py.
3. Generate or update a project config with hls4ml.utils.create_config(...).
4. Use write() to materialize files, compile() for local library builds, and build() only when vendor tools are available and synthesis is intended.
5. Parse existing reports with the hls4ml.report parser APIs instead of rerunning synthesis.

Key constraints

• Treat write() and compile() as safe by default.
• Treat vendor synthesis as expensive and toolchain-bound.
• Prefer the Python API over the deprecated CLI.
• Do not fold precision/resource tuning advice into this sub-skill unless the question is specifically about build or report artifacts.

References

• references/backend-matrix.md
• references/build-and-reports.md
• references/generated-project-layout.md
• references/cli-reference.md
• references/troubleshooting.md