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

Annotations already cover safety (readOnly, idempotent, non-destructive). The description adds the traits that matter beyond them: the strict call-ordering dependency, the once-per-session constraint, and the breadth of coverage. It stops short of describing the return shape (e.g., schema listing format), which keeps it from a 5.

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 critical directive ('REQUIRED... call FIRST') is front-loaded before the use-case enumeration, and the trailing sentences carry the sequencing rules. The long list of query topics is somewhat sprawling but earns its place by driving retrieval across the many sibling workflows.

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 parameters and no output schema, the description carries the full burden and meets it: it says what the tool yields (a schema), why it is mandatory, when to call it, and what to do next (get_query_patterns before SQL). Nothing an agent needs in order to call it correctly is missing.

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 by rule the baseline is 4. There is nothing for the description to compensate for, and it correctly uses the space to describe scope and sequencing rather than inventing param details.

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 names a specific verb+resource (load the database schema) and immediately distinguishes it from siblings by declaring it REQUIRED and 'authoritative source, call FIRST.' The data-scope sentence (10,000+ NYSE/NASDAQ securities, 64 years of prices, financials, indicators, SEC metadata) leaves no ambiguity about what the tool retrieves.

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 states when to use it (any US stock/financial query), the ordering constraints ('call FIRST,' 'once per session before stock_data_query or any workflow tool'), and the follow-up step ('call get_query_patterns before writing any SQL'). This is a full when/when-not/sequencing specification against named siblings.

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