Conciseness

The body is dense with Letta-specific semantics Claude cannot know (backend split, delivery-flag selection, agent-vs-conversation addressing) and wastes little on general knowledge, matching the 'efficient; minor instances of over-explanation' anchor. It is not a 5 because there is noticeable repetition — the --from-agent/sender-identification rules appear in both "How a send reaches the recipient" and the Gotchas, and computer/teleport caveats appear in two sections — that could be trimmed.

Actionability

Every scenario ships copy-paste-ready commands or tool calls with concrete flags and placeholders: `letta -p --conversation <conversation-id> --no-wait --output-format json "message"`, `SendAgentMessage({ conversation_id: "conv-…", message: "…" })`, `letta messages list --conversation <conversation-id> --limit 10`, `letta computers list --online-only`. These cover all the common cases (send-and-forget, wait, reply, check progress, find agent, target a computer), matching the fully-executable 5 anchor.

Workflow Clarity

Each task is a clearly sequenced recipe with explicit decision branches — e.g. the reply section's three reminder cases ("answer in your response" / "use its return address with SendAgentMessage…" / "Answer as you normally would") and the gotcha "If a send's outcome is unknown… read the thread before resending", which is a validation checkpoint. Not 5 because some checkpoints remain implicit (e.g. verifying a receipt's super_run_id against messages status is explained but not woven into a step-by-step check loop), and there is no explicit validate-then-proceed ordering across the send/check flow.

Progressive Disclosure

No bundle files exist (no references/, scripts/, or assets/), and the body is well-sectioned with clearly signaled one-level pointers to related skills ("Load the `finding-agents` skill", "see the `working-across-computers` skill") and `--help` for full flag references. This matches the 'good structure; minor organization gaps' anchor rather than 5, because at ~220 lines some conceptual material (backend internals in "How a send reaches the recipient", the computers section) could live in a reference file to slim the always-loaded body.

Specificity

The description lists four concrete actions — "Send a message to another Letta agent", "continue a thread with one", "check on it", "reply to a message another agent sent you" — which approaches the comprehensive anchor. However, the second-person clause "Use when you need to ask..." violates the third-person voice guideline, reducing specificity by 1 per the rubric; it also omits auxiliary actions like finding agents.

Completeness

It explicitly answers both questions: the 'what' is the four concrete actions in the first sentence, and the 'when' is explicit with concrete triggers — "Use when you need to ask, inform, or coordinate with another agent, or when a message from another agent arrives." This matches the 5 anchor exactly.

Trigger Term Quality

Natural phrases are well covered: "send a message", "reply", "check on it", "ask, inform, or coordinate", "when a message from another agent arrives" — phrasing users would plausibly say. A few natural synonyms ("notify", "ping", "update an agent", "respond") are missing, so it sits at the good-but-not-comprehensive anchor rather than 5.

Distinctiveness Conflict Risk

"another Letta agent" carves out a clear niche that is unlikely to trigger for unrelated messaging or communication skills. Not 4 because the domain qualifier plus agent-to-agent framing leaves only minimal conflict risk with closely related Letta skills (e.g., finding-agents), which is the defining trait of the 5 anchor.