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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds only the vague "on connect" framing and says nothing about result set size, pagination, or what "signed in" means for the listed agents.

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 tight sentence with the resource front-loaded. It is slightly underspecified rather than verbose, and the dangling "on connect" costs a little clarity.

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?

For a simple read-only, zero-required-param tool with full schema coverage and annotations carrying the safety profile, this is adequate but thin. It leaves the relationship to the neighbouring auth tools (sign_in_status, sign_out_everywhere) unexplained.

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?

Schema coverage is 100% and the single optional token parameter is fully documented in the schema, so the baseline of 3 applies. The description adds no format or expiry detail beyond what the schema already says.

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 ("List") plus resource ("every agent currently signed in as your user"), which is distinguishable from siblings like my_invites or sign_in_status. The trailing "on connect" is ambiguous but the core purpose is clear without opening the schema.

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?

No statement of when to use this versus sign_in_status or sign_out_everywhere, and no prerequisites or exclusions. An agent must infer its place among the auth-related siblings.

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