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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely new behavioral context beyond them: a per-call paid cost ($0.004 USDC via x402), the return encoding (base64 plus a data URL), and hard limits (15 markers, 1600 px, 7 styles). It still says nothing about failure behavior or how payment is authorized.

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 sentence that is front-loaded with the artifact type and ends with cost, so the most decision-relevant facts land first. Every clause carries information, though cramming inputs, limits, encoding and price into one sentence makes it slightly harder to scan than a two-sentence split 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 six parameters, no required fields and no output schema, the description covers the essentials an agent needs: what is returned, in what encoding, its size/count limits, and that it is a paid call. Return-value explanation is unnecessary since the format is stated inline.

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 50% (zoom, width, height are undocumented), but the description compensates by supplying the size cap in pixels ('up to 1600 px') and the marker ceiling ('up to 15'), which the schema does not express. The one flaw is that it claims '7 styles' while the schema enumerates only six, which could mislead an agent about available styles.

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 output artifact — a static JPEG map image — plus its two input modes (a single place, or up to 15 numbered markers), so an agent immediately knows this renders a one-shot map image. No sibling (route, isochrone, satellite, geocode) produces this artifact, so differentiation is implicit and clear.

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?

The phrase 'ready for reports, emails and chat' implies intended use cases, but there is no explicit when-to-use rule, no when-not-to-use, and no named alternative (e.g. interactive map, route, isochrone). Usage is only inferable from the described output format.

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