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

Annotations already mark this as a safe, read-only, idempotent, closed-world lookup, so the safety burden is covered. The description adds genuinely new behavior: it returns a "self-contained short answer, check date and URL," which is the key contract for an agent since there is no output schema. It stops short of describing truncation, matching confidence, or fallback when no guide matches.

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 sentence, front-loaded with the country marker and the core verb, and the parenthetical topic list earns its space by defining scope. It is dense but not padded; only minor readability cost from stacking several clauses.

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?

For a one-parameter, annotation-covered lookup with no output schema, the description supplies purpose, topic scope, and return shape. The remaining gap is routing guidance against the many sibling guide/professional tools, which an agent would have to infer.

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 100% and the schema already supplies example queries, so the baseline is 3. The description goes further by enumerating the queryable domains (restricted zone, fideicomiso, notary, deed, financing, resident/non-resident income tax on sale), which helps the agent judge whether its question is in scope and how to phrase it.

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 ("Finds the Payotte guide answering a question about...") scoped to MEXICO, with the topical coverage (buying, financing, selling, renting/owning) spelled out. This differentiates it from cost/price/calculator siblings such as closing_costs_mx, home_prices_mx and mortgage_payment_mx, though it never explicitly routes against the other guide_xx tools.

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 only implied: an agent can infer it should call this for a Mexico home-ownership question. There is no explicit when-to-use/when-not statement, no mention of the parallel guide_au/guide_br/guide_es tools, and no indication of what happens if the question falls outside the listed topics.

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