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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds useful context beyond this: the data source (Yahoo Finance via yfinance), that no API key is required (auth requirement), and the breadth of returned metadata (60+ fields). This goes beyond what annotations provide, earning a 4.

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 moderately long but well-structured: a clear front-loaded purpose sentence, a bulleted 'Use this tool when' section, a list of supported assets, and a source note. Every sentence adds value — no filler. It could be slightly tighter, but the organization makes it easy to scan.

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?

The description covers the tool's purpose, typical usage scenarios, supported asset classes, data source, and authentication requirements. It does not discuss return format, but an output schema exists (which is not shown here) and would cover that. It also doesn't mention limitations or when to prefer a sibling, but for a read-only metadata lookup, the provided context is sufficient for an agent to call it correctly.

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?

Schema description coverage is 0% — the tool description does not mention any of the parameters (symbol, mcp_prompt_id, etc.). However, the description indirectly conveys the core parameter by listing supported symbols and asset classes (e.g., 'AAPL', 'BTC-USD'), which helps an agent infer what to pass for the 'symbol' field. The schema itself already documents each parameter, so the description's marginal addition is the asset-class guidance, not parameter syntax. This partially compensates for the low coverage, but not fully.

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 states a specific verb ('Fetch') and resource ('full Yahoo Finance profile'), enumerates the data returned (name, sector, industry, market cap, P/E ratio, 52-week range, beta, dividend yield, description, and 60+ other metadata fields), and distinguishes it from siblings by focusing on the profile/metadata aspect rather than history, ratings, or filings. It also lists supported asset classes, making the scope unmistakable.

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 provides explicit usage scenarios ('Use this tool when:') covering quick summaries, sector/industry classification, and price metadata needs. It also lists asset classes with examples. It does not explicitly state when NOT to use it or name alternatives (e.g., GetPriceHistory for historical prices), so it lacks exclusions, but the context is clear enough for an agent to route correctly.

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