Conciseness

The body is lean — a one-line rule, a prohibition, the exact command, a compact type table, and three examples — with no padding and no explanation of concepts Claude already knows, matching 'lean and efficient; every token earns its place'; not 4 because there are no over-explanation instances to trim.

Actionability

Provides the exact executable command with named parameters, a type→purpose table, and three copy-paste-ready examples covering common cases, matching 'fully executable; copy-paste ready; specific examples cover common cases'; not 4 because the guidance is complete rather than having minor gaps.

Workflow Clarity

This is a simple single-task skill whose single action (call the script with the right type) is unambiguous, so the simple-skill exception applies; the destructive/batch cap does not apply since sending one inbox message is neither destructive nor batch; not 4 because no checkpoint is meaningfully missing for a single unambiguous action.

Progressive Disclosure

Content is well-organized into clear sections (使い方, type一覧, 例) with a one-level-deep, clearly signaled reference to scripts/inbox_write.sh, matching 'good structure; references mostly clear; minor organization gaps'; not 5 because the referenced scripts/inbox_write.sh is absent from the bundle, and not 3 because the structure and signaling are genuinely good rather than merely adequate.

Specificity

Names the domain (agent-to-agent messaging) and one concrete action ('別エージェントのinboxにメッセージを送信する') but lists only a single action, matching the anchor for 'domain and 1-2 concrete actions, not comprehensive'; it is not 4 because there are not several specific actions, and not 2 because the action is concrete rather than generic.

Completeness

Provides a clear 'what' (sends messages to another agent's inbox, the sole agent-to-agent means) but no 'Use when...' or equivalent trigger guidance, so the missing-'when' cap at 3 applies; not 4 because 'when' is entirely absent rather than just weakly implied.

Trigger Term Quality

Contains some natural phrases a user might say ('メッセージを送信', 'inbox', 'agent-to-agent通信') but misses common variations and synonyms, fitting 'some relevant keywords but missing common variations'; not 4 because keyword coverage is thin rather than good.

Distinctiveness Conflict Risk

'agent-to-agent通信の唯一の手段' carves a clear, distinct niche with minimal conflict risk, matching 'mostly distinct; minor overlap risk'; not 5 because there are no explicit distinct trigger phrases, and not 3 because the 'sole means' framing is more specific than 'somewhat specific but could overlap'.