Conciseness

The body is dense tool tables plus one exact command sequence, with no explanations of concepts Claude already knows; every line delivers a tool, parameter, or operational constraint. Even the apparent asides earn their place (e.g., 'Tailscale is only the ssh transport, the same as any LAN or internet address' prevents a real misreading, and the LaunchAgent/Aqua-session note is non-obvious operational detail). This matches the 5-anchor ('lean and efficient; every token earns its place') rather than the 4-anchor, which requires trimmable over-explanation.

Actionability

The ssh setup section is copy-paste ready ('curl -fsSL https://cua.ai/install.sh | sh -s -- -y --select spaces,host --no-onboarding', 'cua host setup --profile spare --name "<name>"', 'create_space(on="host:<name>", count=2)') and key tools list parameters ('space_bash' with 'space, command, optional timeout'; 'agent_start' with 'space, agent, prompt'). It falls short of the 5-anchor because several tools are described only by purpose without invocation detail ('stream_endpoint' — 'Get a ticketed media URL'; 'agent_status / agent_message / agent_stop / agent_list' — 'Follow, steer and stop runs'; 'open_space_viewer' with no arguments shown), which are minor but real gaps.

Workflow Clarity

The ssh host setup is a clearly sequenced 6-step process with a real checkpoint (show the device code and URL and have the user approve), but the skill's lifecycle workflow ends in destructive operations without any validation or confirmation step: 'A cloud Space costs money: delete the ones you created when the task ends' and 'delete_space — Delete a Space's sandbox and stop metering' involve irreversible deletion with no verify-first checkpoint (e.g., confirm files are downloaded or ask the user). Per the judging guidelines, missing validation in workflows involving destructive operations caps workflow_clarity at 3; the sequence itself is better than the 2-anchor but does not meet the 4-anchor's 'most checkpoints present'.

Progressive Disclosure

Sections are well organized (Get a Space / Work in it / Show it / Agents, apps and network / host setup / Rules) and no references are buried, matching the 4-anchor ('good structure; most content appropriately placed'). It cannot take the 5-anchor's simple-skill exception because the body is ~84 lines (over the ~50-line guideline), and the specialized ssh host-setup procedure — a distinct advanced topic — is fully inlined rather than split into a reference file, a minor organization gap.

Specificity

The description lists multiple concrete, comprehensive actions ('run commands in it, move files in and out, show its desktop or a single window on the user's screen, start coding agents inside it, teleport a signed-in app session into it, and share the host's network with it'), which matches the 5-anchor, but it uses second person ('the user can watch; you can run commands in it'), which the judging guidelines penalize by reducing specificity by 1. It is above the 3-anchor ('1-2 concrete actions') and the 4-anchor ('minor gaps in coverage') because action coverage is essentially complete, not partial.

Completeness

It explicitly answers both questions: the 'what' is a concrete list of capabilities, and the 'when' is an explicit 'Use when...' clause with concrete trigger phrases ('the user mentions Spaces, asks you to do work "in a Space", or wants a task isolated but visible'). This matches the 5-anchor exactly; the 4-anchor ('when' could be more explicit or specific) understates how direct the trigger guidance is.

Trigger Term Quality

'Use when the user mentions Spaces, asks you to do work "in a Space", or wants a task isolated but visible' gives good natural trigger phrasing including a quoted exact phrase users would say. It falls short of the 5-anchor because common synonyms are missing (e.g., 'remote machine', 'sandbox', 'isolated environment', 'virtual desktop'), but it clearly exceeds the 3-anchor's 'missing common variations'.

Distinctiveness Conflict Risk

The niche is clearly defined by the product-specific terms 'cua Spaces' and 'the cua MCP server', with distinct triggers ('Spaces', '"in a Space"') unlikely to fire for unrelated skills. Only 'wants a task isolated but visible' has slight overlap risk with sandbox/VM skills, which keeps it at the 5-anchor ('minimal conflict risk') rather than suggesting the 4-anchor's 'minor overlap risk'.