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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds the 'real-time' qualifier and return fields but does not disclose additional behavioral aspects such as rate limits or data freshness caveats. It is consistent with annotations, so not contradicted.

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-sentence description with no filler. The first sentence identifies the action and resource; the second lists returns and usage. Every sentence earns its place and is front-loaded with the core purpose.

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 adequately explains return values (ASI, market cap, volume, deals, advancers, decliners) and provides usage context. For a parameterless, read-only tool, this fully satisfies the contextual needs for an agent to select and invoke it.

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 has zero parameters, so schema coverage is effectively complete and the description has no parameter semantics to add. Baseline of 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?

Description states 'Get a real-time overview of the Nigerian Stock Exchange (NGX)' and lists specific return metrics (ASI, market capitalisation, trading volume, deals, advancers, decliners), clearly distinguishing it from siblings like get_ngx_top_gainers which focus on subsets.

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 when the user asks about the Nigerian stock market at a high level,' providing clear context. However, it does not name alternatives or state when not to use, so it lacks full exclusion/alternative guidance.

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