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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, so the safety profile is covered. The description adds genuine context in the 'user-controlled browser bridge' heartbeat concept, but says nothing about what a stale heartbeat means operationally, what failure modes exist, or what the result looks like.

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?

One sentence, no filler, verb and scope front-loaded. It is dense and readable, though it packs two distinct checks (session liveness, bridge heartbeat) without separating them.

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?

There is no output schema, so the description should hint at what is returned (alive/not-alive plus heartbeat freshness), and it only partially does so. Combined with zero parameter documentation in either schema or description, an agent has enough to know the intent but not the full calling contract.

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 description coverage is 0% and both required parameters (session_id, agent_token) are undocumented in the schema. The description never mentions either parameter, so it fails to compensate for the coverage gap on a tool that requires authentication and a session identifier.

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?

States a specific verb ('Check whether') and a precise resource: a scoped GhostKey browser session's liveness plus bridge heartbeat freshness. 'Scoped session' separates it from the sibling ghostkey_status (global) and from ghostkey_session_create/revoke/action, though no sibling is named explicitly.

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 implied by 'check whether ... is alive', but the description never states when to call this versus ghostkey_status or ghostkey_device_pairing_status, nor any prerequisite such as holding a valid agent_token.

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