Inspect every registered OneHome session

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

Annotations provide readOnlyHint and idempotentHint, so the description doesn't need to re-state that. It adds value by explaining the semantics of active_session_id and the defaulting behavior of other tools, plus the error behavior for multiple matches. This goes beyond the structured annotations, though it could mention that it doesn't mutate state explicitly, but the annotations already cover that.

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?

The description is a single dense paragraph that packs a lot of information, but it remains concise and relevant. It front-loads the purpose, then explains routing and default behavior. While it is longer than strictly necessary, every sentence contributes to understanding the tool's behavior.

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 tool with no parameters and no output schema, the description thoroughly explains what the output will contain (session_id, auth_mode, token expiry, session scope, active_session_id), how the output is to be interpreted (routing and defaults), and the common use case. Nothing essential is missing for an agent to invoke it correctly.

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?

The schema has zero parameters, and the description clearly states that no input is required. Since there are no parameters to document, the description appropriately focuses on the output semantics, which meets the baseline for a parameterless tool.

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?

The description clearly states that the tool returns one entry per registered session with a specific set of fields, and it differentiates from siblings by explaining its role in session inspection and default resolution. The verb 'returns' and resource 'registered session' are specific and unambiguous.

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?

The description explicitly says when to use it (to see defaults and session context, especially for single-session use) and when not to use it (when there are several matches, it errors and directs to use onehome_set_active_session). It also explains the routing behavior and the common case, providing clear usage guidance.

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