[Feature]: Argument hints for `/speckit.*` Claude Code commands

[Heremeus]

Problem Statement

When using slash commands like /speckit.constitution or /speckit.specify in
Claude Code, no hint is shown indicating that user input is expected. This leads
users to run the commands without arguments, resulting in degraded output. For example:

• /speckit.constitution silently falls back to defaults assumed by Claude
• /speckit.specify responds with "The feature description was empty. Please
  provide a description of the feature you'd like to specify."

There is no in-UI signal that arguments are required or even supported, which
creates a confusing first-time experience.

Proposed Solution

Claude Code command files support an argument-hint front matter field that
displays an inline prompt to the user when they invoke a command. Adding this
field to all relevant Spec Kit command files would surface the expected input
before the command runs.

Example for /speckit.specify:

argument-hint: Brief description of the feature you want to specify

This surfaces directly in the Claude Code UI as the user types the command,
making it immediately clear what input is expected.

Alternatives Considered

No response

Component

Agent integrations (command files, workflows)

AI Agent (if applicable)

Claude Code

Use Cases

No response

Acceptance Criteria

• All Claude Code commands that accept user input have an argument-hint
  that accurately describes the expected argument

Additional Context

• Claude Code argument-hint docs:
  https://docs.anthropic.com/en/docs/claude-code/slash-commands

[mnriem]

@Heremeus Is argument-hint universally supported across all agents?

[Heremeus]

@mnriem I'm not sure if I fully understand the question. argument-hint is only supported for slash commands in claude code (.claude/commands/) as far as I'm aware. Are the command markdown files generic across all coding assistants?

[mnriem]

No they are not, well actually they are before they land, but I was asking from a perspective of "Can this benefit all agents". If this is Claude Code specific then when it gets chosen with --ai it will have to add that to the template files on the fly. Feel free to create a PR and we can review it.