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

The description frames this purely as retrieval ("Get market data", "Recent market data the warehouse lags on") and never mentions mutation, yet the annotations declare readOnlyHint=false and idempotentHint=false. The description therefore contradicts the declared behavior profile rather than complementing it, which is the exact failure mode the rubric scores as 1.

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 sentences, front-loaded with the resource and its contents, then the data_type selection rule, then the sibling alternative. Every sentence carries information, though the middle sentence is dense enough that it could be split for scanability.

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 full schema description coverage, an output schema covering return values, and only four parameters, the description supplies the missing pieces an agent needs: what data comes back, how to choose data_type per asset class, and which sibling handles filings. Its only gap is the unresolved conflict with the read-only annotation.

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 coverage is 100%, so the baseline is 3, and the description genuinely adds meaning beyond the enum: the asset format selects which market is queried, and price_history is the right data_type for stocks, currency pairs, and commodities. It does not explain the interaction between limit/frequency, but those are already documented in the schema.

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 data") and enumerates the exact content classes returned: quotes, OHLCV, company profiles, FX, and commodities. It also draws a boundary against a named sibling, routing financial statements and reported facts to search_company_filings, so an agent can distinguish it without opening the schema.

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?

Gives concrete routing guidance — "Set data_type to price_history for stocks, currency pairs, and commodities" and the note that the asset format determines which market is queried — plus one explicit alternative (search_company_filings for financial statements). It stops short of stating when-not-to-use relative to other siblings such as get_series or search_news.

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