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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this while adding genuinely new context: it returns public registry data and requires no API key. It does not mention rate limits or pagination, but the openWorldHint and output schema cover the rest.

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?

Three tight sentences with the purpose and returned fields front-loaded, followed by the usage routing and the safety/auth note. Every sentence earns its place with no redundancy.

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?

An output schema exists, so return-value documentation is not required, yet the description still names the key fields. Purpose, workflow position, and auth requirements are all covered for a zero-param discovery 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?

This tool takes zero parameters, so the baseline is 4. The description does usefully explain where the returned slug is consumed (the product param on other tools), adding cross-tool meaning even though there are no local params to document.

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 ('List the product streams this API serves') and enumerates the returned fields (slug, name, description, web path, filters, use cases). It clearly distinguishes itself from siblings by positioning itself as the discovery step before read tools like query_security_feed and get_latest.

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?

Explicitly says 'Use this first when you are unsure which stream fits your task' and names the exact downstream tools (query_security_feed, get_latest) plus how to chain the result (pass the slug as the product param). Both the when-to-use and the follow-up action are spelled out.

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