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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds value the annotations cannot: it discloses the shape of each returned record (slug, party_shapes with its allowed values, children boolean, pace with its allowed values) and notes the result set is paged, which matters because there is no output schema.

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 tight sentences that front-load the definition, then the return composition, then the downstream use of slugs. The colon-and-list construction is dense but readable; the only inefficiency is that "with their slug and audience:" reads awkwardly as a lead-in to the field list.

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 in play, the description carries the return-value burden and does so by naming every returned field and its possible values. Combined with the paging note and the slug-usage hint, an agent has everything needed to call it and consume the result without further inference.

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% — lang, limit, offset and status are all documented in the schema with defaults, bounds and enum meanings. The description contributes only the word "Paged." and does not explain language fallback behaviour or how the default published status affects results, so the schema does the heavy lifting. Baseline 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?

States a specific verb and resource ("List the personas") and immediately defines what a persona is with concrete examples (foodie, collector), so an agent unfamiliar with the domain can map it to 'traveller type'. It also names the sibling concept get_persona covers implicitly by using the enumeration verb, and enumerates the returned fields (slug, party_shapes, children, pace).

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?

"Persona slugs are used with city slugs to name an itinerary" tells the agent exactly why it would call this tool — slug discovery before a naming call. It stops short of explicitly excluding get_persona (single lookup) or stating when to prefer one over the other, so it is clear context without full routing guidance.

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