[Feature]: Support file references for workflow inputs

[markuswondrak]

Problem Statement

Currently, workflow inputs must be passed directly via the command line (e.g., --input key="value") or through interactive prompts. When working with complex workflows, long prompts, or extensive feature specifications, passing large blocks of text as inline strings is cumbersome, hard to read, and error-prone due to escaping issues.

Proposed Solution

It would be highly beneficial to support passing workflow inputs via file references. For example, allowing syntax like:

• --input-file payload.json
• --input spec=@path/to/file.md

This would allow developers to maintain complex inputs in version-controlled files and easily pass them to the workflow engine.

Alternatives Considered

• Copy-pasting large text blocks directly into the terminal prompt.
• Writing custom shell wrapper scripts to read files and interpolate their contents into the CLI command, which quickly becomes difficult to maintain when handling quotes and special characters.

Component

Specify CLI (initialization, commands)

AI Agent (if applicable)

None

Use Cases

No response

Acceptance Criteria

No response

Additional Context

No response

[Adr1an04]

I’d like to take this one, if thats okay with you @markuswondrak

I’m going to test the behavior described above first, then work on a fix for --input spec=@path/to/file.md

[mnriem]

Note workflows are not required to start with a speckit command so as such we should not expect it to be just called --input spec=@. It should should logically map onto how information is now shared between steps and make it possible to either pass it as an parameter directly on the command line or as a parameter file. And more than one should be supported