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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful context beyond annotations: lists are fixed and immutable ('thresholds, sector exclusions and ranking are fixed'), output is 'screen output, not recommendations,' and notably 'neither label forecasts a return.' This last warning about the value trap label not being reliable guidance is valuable.

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 well-structured paragraphs, each with a distinct purpose: output definition, usage guidance, and behavioral caveat. The description front-loads the core purpose in the first sentence and moves to usage in the second paragraph. Every sentence earns its place with substantive content; no filler.

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 parameterless tool with strong annotations (readOnly, idempotent, openWorld) and no output schema, the description is remarkably complete. It explains what the lists contain, how they're defined, when to use them, when not to, and even caveats about their interpretive limits. The only minor omission might be that no output schema exists, but with zero parameters and a fixed, published output, the description covers everything an agent needs.

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 there are no parameters to describe, so the baseline of 4 applies. The description adds the meaningful context that the tool is parameterless and that all thresholds/criteria are fixed to the published page, which clarifies why no parameters exist.

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 names the specific resource ('two published monthly Brina Matrix lists'), names both list labels (Double Discount, value trap), and explains the distinct screening criteria for each. It distinguishes itself from siblings by explicitly noting it 'takes no parameters' and covers only the fixed published screen, which separates it from screen_stocks and get_stock_valuation.

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?

Excellent usage guidance: 'Use when the user asks what the framework currently flags, or asks about the Double Discount or value trap lists by name.' It also gives explicit exclusions with named alternatives: 'Do not use it for custom criteria (use screen_stocks) or for one named company (use get_stock_valuation).' This is exemplary when/when-not usage guidance.

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