See what a session is doing and what is asked of it

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnlyHint=true, so the safety profile is already covered. The description adds real value beyond that by disclosing the shape of the read: unread messages, held digests, open tasks, last shown/answered timestamps, and a drift comparison. It does not mention permissions, visibility scope (same workspace vs. cross-workspace), or staleness/refresh behavior, which keeps it out of the top band.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence that opens with the action and then enumerates the payload categories; there is no filler or redundancy. The parenthetical list is dense but each item carries information, so it stays readable rather than sprawling.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With one fully documented parameter, a readOnly annotation, and no output schema, the description must describe what comes back and largely does so via the enumerated categories. What remains thin is operational context: scope/permissions for viewing another session and whether the status is live or cached.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There is a single parameter with 100% schema description coverage, so the schema already defines it as 'Session name or ref from list_peers'. The description adds no additional semantics for the peer argument (e.g., whether an unknown peer errors or returns empty). Baseline 3 applies when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb (show) plus resource (another session's current state) with a clear enumeration of what is reported: work in progress, pending items, last activity, and drift. It reads as distinct from list_peers, which enumerates sessions rather than reporting one session's state. It stops short of explicitly contrasting with the overlapping sibling message_status, which also concerns message activity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: the agent infers 'call this when you need to know about another session'. There is no explicit when-to-use, no when-not-to-use, and no named alternative such as list_peers (for enumeration) or message_status (for message-level detail). The peer parameter's reference to list_peers hints at ordering but is not stated as guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.