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

Annotations already cover readOnly, idempotent, non-destructive and closed-world, and the description largely restates them ("sin red, sin estado guardado", deterministic). It earns credit for information annotations do not carry: the 64 KB input cap, 1 s per call and 1 MB result limit, and the bidirectional mode of operation.

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?

Front-loaded and well-ordered: purpose, when, not-for, side effects, determinism, limits. It is somewhat inflated by the full Spanish/English duplication plus a meta line pointing at inputSchema.description, which adds length without adding meaning, but no single sentence is filler.

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 an output schema present, return values need no explanation, and the description covers mode selection at a high level, determinism, safety and execution limits. The remaining weakness is the unstated mutual exclusivity of the coordinate pairs, which is exactly what an agent needs to build a correct call.

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%, so each of x/y/lat/lon/zoom is already documented with types, ranges and the "to bbox" vs "to tile" mode marker. The description adds the same zoom 0-24 range and the two-mode idea via "o una tesela a su caja", but never states that lat/lon and x/y are mutually exclusive alternatives — the one semantic gap the schema also leaves implicit. Baseline 3.

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 concrete verb and resource: converts lat/lon + zoom to Web Mercator XYZ tile coordinates and quadkey, or the inverse (tile to bbox), with the zoom range spelled out. It differentiates against geohash-encode, though not against the closer neighbours utm-from-latlon or geo-bounding-box, so the sibling boundary is only partly drawn.

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?

Has an explicit "Cuándo" clause and a "No para" clause that names the alternative tool (geohash-encode) and the condition selecting it. The guidance is concrete, but only one of several plausible competing siblings is excluded, and the "distances, bearings or areas" phrasing overlaps with geo-haversine/geo-bearing rather than this tool.

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