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

readOnlyHint=true already tells the agent this is a safe read with no side effects, so the description's remaining burden is smaller. It does add real value by disclosing the methodology (QQQ trend and momentum) and the output value space, but says nothing about freshness/staleness of the regime, or whether the classification is cached or computed on request.

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?

A single sentence that front-loads the verb and resource, then adds scope, value set, and method in the right order. No filler, no restatement of the name.

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?

With no output schema, the description carries the return-value burden and does so by enumerating the three regime labels plus the basis for the classification. For a zero-parameter read tool that is essentially complete; only the update cadence / time horizon of 'current' is left unstated.

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, so there is nothing for the description to disambiguate. The baseline of 4 applies; the description correctly signals a no-argument call by not implying any filtering options.

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 (get market regime), narrows the scope to tech stocks, enumerates the possible values (bullish, neutral, bearish), and names the underlying signal source (QQQ trend and momentum). An agent can distinguish this from get_stock_score or get_all_scores purely on subject matter — aggregate regime vs. per-stock scores.

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?

Usage is implied rather than stated: the tech-stock/QQQ framing suggests when the tool is relevant, but there is no explicit 'use this when you want a macro read vs. get_stock_score for a single name' routing. No prerequisites or exclusions are mentioned.

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