x_trends

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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive. The description adds behavioral context beyond annotations by stating the data is tied to the signed-in account and that location/personalization are controlled externally, which is not visible in annotations.

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?

The description is a single, tightly scoped sentence. It front-loads the core action and resource, and every phrase ('signed-in account', 'Trends surface', 'controlled by X') earns its place by conveying or constraining meaning.

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 low-complexity, read-only tool with rich annotations, the description is nearly complete. It explains the scope and a key limiting trait (external controls). Minor gaps include parameter behavior (limit, maxScrolls) and return format, but these are not critical given defaults and the simple nature of the tool.

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 0%, so the description should compensate for parameter meaning. It does not mention 'limit' or 'maxScrolls', though the parameter names and schema constraints (defaults, min/max) provide some inferable meaning. The description adds no value here.

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 names a specific verb ('Read'), a clear resource ('trend cards'), and a specific surface ('Trends surface'). It also notes the account-scoped, platform-controlled nature of the data, which differentiates it from siblings like x_search or x_timeline without needing to open those schemas.

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 description implies a narrow use case: reading the signed-in account's Trends surface. It does not explicitly name alternatives or state when not to use this tool, but the mention of 'controlled by X' implies that user-controlled personalization is not available, suggesting a distinction from search-like tools.

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