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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: the persona comes back in a fresh session with continuity (accumulated turn count preserved) and an inline living-body view. It does not discuss failure modes for a stale or unknown persona_id.

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?

Three short clauses: what it does, what it returns, when to use it. Front-loaded with the core action and no filler or redundancy.

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 no output schema, the description correctly takes on the burden of listing return values (name, model, turn count, living-body view). Combined with annotation-covered safety and a fully described single parameter, an agent has everything needed to select and call it.

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 100% and the single parameter is fully documented as 'the persona_id returned by create_agent_persona.' The description reinforces that the id addresses an existing saved persona but adds no format, length, or lookup detail beyond the schema, so the baseline of 3 applies.

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 gives a specific verb + resource ('Bring back a previously saved persona by its persona_id') and even enumerates what is restored (same body and identity, fresh session). It implicitly separates itself from create_agent_persona via 'previously saved,' but never names that or any other sibling, so the differentiation is inferred rather than stated.

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?

It gives an explicit trigger: 'Use this when a conversation starts and the user returns to a named agent.' That is clear context, not just implied usage. However, it offers no negative guidance (e.g., what to do if the persona_id is unknown, or that this must not be used to create a new persona).

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