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

Annotations already declare readOnly=false, openWorld=true, idempotent=false and destructive=false, so the description's job is to add context — and it does: it discloses that a public link is created (an external exposure the annotations don't convey), that missing coordinates trigger a name-based lookup, and that personal details are prohibited. It stops short of saying what happens on a repeat save, which matters given idempotentHint=false.

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?

A single dense paragraph that front-loads the action and result, then the item rules, then the privacy constraint. Every sentence carries information, though the run-on structure makes the item-optionality clause slightly harder to scan than a short list would be.

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 does state the key return value (a public link) and the downstream effect of opening it. For a three-parameter write tool with nested items, the remaining gap is the response shape and duplicate-save behavior, which is a modest omission rather than a blocking one.

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 coverage is only 33%, so the description must compensate, and it does for the item fields: name is required, lat/lng, address, kind, note and day are optional, and items without coordinates are geocoded by name. It does not explain trip_name or city, nor the 40-item cap or the day 1-30 range, leaving some gaps.

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 ('Save a trip ... to GeoTok') plus the concrete outcome (public link, places pinned on the user's map, proximity reminders). This clearly separates it from the sibling search/plan tools, which retrieve or draft rather than persist a shareable artifact.

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 the outcome (you save a trip once you have places to keep), but there is no explicit when-to-use or when-not guidance and no mention of the obvious alternative, plan_trip. An agent must infer that this is the persistence step after planning.

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