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

With no annotations, the description must disclose behavioral traits. It reveals that providing api_key changes the output from generic synthesis to personalized, but doesn't describe other behavior like read-only nature, response format, or error handling. That's a moderate gap.

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 two sentences, front-loaded with purpose, and every word earns its place. No fluff.

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 tool with one optional parameter and no output schema, the description covers the essential usage and intent. It could mention what the brief contains, but that isn't necessary for invocation.

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 description adds meaning beyond the schema by explaining that api_key yields a personalized brief while omitting it yields the latest market synthesis. This clarifies the parameter's effect beyond the schema's 'for personalized brief (optional)'.

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 clearly states the tool delivers 'Troy's daily market brief' and distinguishes it from sibling tools like get_stack_signal and get_analytics. The verb 'get' is implied and the resource is specific and named.

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 explains when to use an api_key ('for personalized brief') and when to omit it ('for the latest Stack Signal market synthesis'), giving clear context. It doesn't explicitly name alternative tools, but the usage conditions are well-specified.

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