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

Annotations only declare readOnlyHint=true and openWorldHint=false, yet the description adds substantial non-obvious behavior: the three operational modes, the 5-month compare cap and 12-month scan cap with top-5 return, and the free/Pro pricing boundaries tied to date range. That is genuine context the annotations cannot convey.

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 with the trigger condition, then modes, gating, and returns, then sibling routing — a logical order. It is dense but slightly redundant, restating the free/Pro boundary that the monthRange schema description already carries.

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 return burden and does so ('month score, element breakdown, adverse alerts'). Combined with modes, gating rules, and sibling routing for a 6-param nested tool, an agent has everything needed to call it correctly.

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%, so the baseline is 3, but the description earns more by reconciling the confusing schema (compareMonths maxItems=4) into 'compare up to 5 months' via targetMonth, and by stating the 12-month scan cap returns only the top 5. It does not explain the category enum weighting or birthInfo override beyond the 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?

States a precise trigger and resource: month-granularity intention analysis for selecting a month. It explicitly differentiates from siblings by naming intentions_ask_day and intentions_ask_hour and the granularity condition that selects each, so an agent can route without opening another schema.

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?

Gives concrete example phrasings ('how is next month', 'best month in 2026 to X'), enumerates decision categories (trip-month, launch, content calendar, quarterly/annual), and names the alternative tools with the exact condition that switches to them (day vs hour precision).

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