mcpx: zsh completion script fails to parse (unquoted _describe entries) #272

Bug

mcpx completion zsh generates a script that zsh cannot parse.

This is the same defect as dezren39/darwin-nix#365 (fixed there by PR #379), present in this repo's pkgs/mcpx copy: the fix was never ported here. pkgs/mcpx/internal/cli/completion.go (~line 92, zshCompletion) still emits each _describe commands entry unquoted:

fmt.Fprintf(&b, "    %s:%s\n", c.Name, zshEscape(c.Summary))

Summaries carry apostrophes, parentheses and glob brackets — e.g. prompts: list or render a server's prompts (manual.go:414) and search: find tools by name and description (keyword or semantic). zshEscape turns ' into '\'', which is only valid inside single quotes, and leaves parens/brackets bare.

Reproduction (verified on main a29abd3, 2026-10-18)

$ go build -o /tmp/mcpx ./cmd/mcpx   # in pkgs/mcpx
$ /tmp/mcpx completion zsh > comp.zsh
$ zsh -n comp.zsh
comp.zsh:192: parse error near `;;'
$ echo $?
1

Generated array (excerpt):

    prompts:list or render a server'\''s prompts
    resources:list or read a server'\''s resources
    search:find tools by name and description (keyword or semantic)

No existing issue in this repo tracks this (gh search issues --repo developing-today/code zsh → none); there is also no internal/cli/completion_test.go in this copy.

Why it matters

Anyone who installs the zsh completion gets a script their shell rejects at load — the completion feature is simply broken for zsh users, silently. It was already diagnosed and fixed once in the sibling copy; letting the copies drift means users here keep the broken version.

Suggested fix (mirrors dezren39/nix PR #379)

• Emit each commands entry single-quoted: '%s:%s' with a new zshDescribe helper that only handles _describe's own syntax (backslash-escape : inside the description, '\'' for apostrophes) instead of reusing zshEscape.
• Keep zshEscape for the flag-description sites, which are already inside single quotes.
• Port the regression tests from nix (internal/cli/completion_test.go): every commands entry is single-quoted, an apostrophe-bearing entry is present, and zshDescribe escapes colons/quotes.

Acceptance criteria

• mcpx completion zsh | zsh -n exits 0
• bash/fish completions still parse (bash -n, fish -n or equivalent)
• New regression tests in internal/cli fail on the pre-fix code and pass with the fix
• go test ./internal/cli/ passes