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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds a genuine scope signal by stating it also covers what SwiftPrism does not do, but it says nothing about return format, tier-specific differences in the response, or auth requirements.

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 compact sentences, front-loaded with the tier scope before the feature list. The feature enumeration is dense but each item earns its place as a content preview; the trailing 'also what SwiftPrism does not do' clause is slightly vague but short.

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 zero-param informational tool with no output schema, the description conveys roughly what topics the response covers but not the shape of the response (flat list? per-tier breakdown? prose?). It is adequate to call the tool but not to predict or parse the result.

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?

The tool takes zero parameters and the schema is empty with additionalProperties false, so there is nothing for the description to disambiguate. Baseline 4 applies.

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 enumerates the content covered (headlines, Headline Voice, Market Momentum, holdings, languages) and states it covers Elite and Free tiers, so an agent can infer this returns a feature/availability listing. However, there is no verb ('returns', 'lists') and no differentiation from siblings like get_plans or get_languages, which cover overlapping subscription information.

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?

No when-to-use guidance, no prerequisites, and no mention of alternatives. The agent is not told to call this before start_trial or instead of get_plans, so routing between the four siblings is left entirely to inference.

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