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

Annotations already cover the safe-read profile (readOnlyHint=true), so the description need not restate that. It adds genuine behavioral context: the 12-month window, the riser/faller semantics, and especially the 30+ sales filter with its rationale ('thin-volume noise is excluded'), which explains why certain communities may be absent. It doesn't disclose result ordering or return structure, but those are minor for a read-only list.

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?

Two sentences of about 30 words total. The core resource-and-metric statement is front-loaded, the direction semantics follow immediately, and the volume filter closes with a justification. No filler or repetition of schema content.

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 simple 2-parameter read tool with readOnlyHint and no nested objects, the description covers the essentials: what is returned, the metric, the direction choices, and the data-quality filter. Gaps are minor: no explicit result ordering (e.g., sorted by magnitude) and no return-shape details, which matter more because there is no output schema. Sibling differentiation could also be stronger.

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?

With 0% schema description coverage, the description must compensate. It does explain the required parameter direction ('up' = risers, 'down' = fallers), which carries real semantics the enum values alone lack. However, the limit parameter is never mentioned; it is only structurally constrained in the schema (min 1, max 10, default 5). Partial compensation only.

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 resource (communities) and metric (biggest 12-month price moves), with direction semantics spelled out ('up' = risers, 'down' = fallers). The 30+ sales threshold adds precision. It doesn't explicitly differentiate from the sibling rank_communities, which could overlap, so it stops short of a 5.

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 implied: call this when you want communities ranked by 12-month price movement, and the direction field tells the agent which list to request. However, with 11 siblings including rank_communities and get_price_history, there is no explicit when-to-use or when-not-to guidance, leaving the choice to inference.

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