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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the account/consent precondition and mentioning that source/freshness metadata accompanies the data. It does not describe pagination or result volume, keeping it short of a 5.

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 core sentences are tight and front-loaded, but the line 'Units: ft, kt, s, F, mi; directions FROM' appears to be boilerplate copied from a measurement-oriented sibling and is meaningless for a zero-parameter saved-places list, so it does not earn its place.

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 carries the burden of explaining the return, and 'Returns data and source/freshness metadata' is vague about what a saved-places listing actually contains. The account prerequisite is covered, but the misapplied units boilerplate and thin return description leave gaps for a simple read tool.

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 takes zero parameters, so per the baseline rule parameter semantics is a 4. There is nothing for the description to clarify beyond the empty schema.

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 verb and resource: 'Read your saved places and favorites.' An agent can distinguish it from get_my_place (singular) and list_my_trips, though it never explicitly contrasts those siblings. Purpose is clear without sibling differentiation.

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 a genuine prerequisite ('Requires your Gillby account and explicit account consent'), which is useful context for selection. However, it never says when to use this versus get_my_place or list_my_trips, and no exclusions or alternative routing are offered.

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