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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds value beyond them by stating the return format (Markdown), that it takes no input, and that its guidance applies only to plans persisted in Mappu — context an agent cannot infer from the annotations alone.

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 front-loaded sentence that leads with the core purpose ("Optional reference for the format of a plan saved with mappu_save_trip_plan") before enumerating coverage areas. The middle clause listing content domains is somewhat run-on, but every element is informative and nothing is redundant.

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 must disclose the return shape, which it does ("returns Markdown"), along with the scope of what the guide covers and the condition under which it is relevant. For a parameterless, read-only reference tool, an agent has everything needed to decide to call it and what to expect.

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 tool has zero parameters, so the baseline is 4. The description reinforces this by explicitly stating "Takes no input," which confirms the empty schema is intentional rather than an omission.

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 states a specific resource (a reference guide describing the format of a trip plan) and its content domains: day handling, timing, opening days, season, places' background, food and practical tips, and field mapping. It also anchors itself to the sibling tool mappu_save_trip_plan, so an agent can distinguish it from the other mappu_* tools without opening any 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?

"Optional reference ... useful before writing a plan the traveler wants to keep in Mappu" gives a clear trigger point, and "It applies only to plans saved to Mappu" sets an explicit scope boundary that tells the agent when not to bother. It does not name an alternative sibling to consult instead, which keeps it just short of a 5.

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