mcp_cli_tools_prompt: concept explanation stripped; safe_outputs_prompt contradicts CLI framing

[dsyme]

Problem

Two related issues in the generated agent prompt that together leave the agent without a clear understanding of what safeoutputs is or how to invoke it.

1. mcp_cli_tools_prompt.md lost all concept explanation (Jun 3, commit 04ef6cc)

PR #36778 replaced the 68-line mcp-clis block with a 5-line stub in the name of prompt size reduction. The removed content included:

• An explanation that CLI servers are standalone executables invoked from bash (not MCP tools)
• A clear statement that safeoutputs and mcpscripts must be called as CLI commands, not via MCP
• Concrete bash examples for safeoutputs, playwright, and mcpscripts
• The JSON stdin approach with a real example

The current block gives an agent no mental model of what a "CLI server" is:

<mcp-clis>
CLI servers are available on `PATH`:
- `safeoutputs` — run `safeoutputs --help` to see available tools
Use `<server> --help` for tool names, parameters, and examples before calling any command.
To pass many arguments safely, pipe a JSON object on stdin with `printf` and pass `.` as the payload sentinel: ...
</mcp-clis>

2. safe_outputs_prompt.md line 2 calls safeoutputs an "MCP server" — contradicting the CLI framing

gh CLI is NOT authenticated. Use safeoutputs MCP server tools for GitHub writes...

The agent is simultaneously told in <mcp-clis> that safeoutputs is a "CLI server" and in <safe-outputs> that it is an "MCP server". An agent that doesn't understand the concept may fall back to trying MCP tool calls.

Impact

Observed in run https://github.com/github/github-automation/actions/runs/27649385891/job/81769559261#step:15:12 — the generated prompt has both contradictory descriptions and no explanation of the CLI invocation model.

Suggested fix

1. Restore a brief concept sentence to mcp_cli_tools_prompt.md, e.g. "Each server is a standalone executable on PATH — invoke it from bash like any shell command (e.g. safeoutputs add_comment --item_number 42 --body "...")."

2. Fix line 2 of safe_outputs_prompt.md to say "CLI tool" instead of "MCP server":

   • Before: Use safeoutputs MCP server tools for GitHub writes
   • After: Use the safeoutputs CLI tool for GitHub writes

References

• Commit that stripped the prompt: 04ef6cc988 (PR Replace MCP CLI system-block prompt with slim version (no feature flag) #36778)
• Contradicting file: actions/setup/md/safe_outputs_prompt.md line 2
• Current slim prompt: actions/setup/md/mcp_cli_tools_prompt.md