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

The description goes well beyond the readOnly and destructive hints by disclosing crucial behavioral quirks: Quantity is a balance not daily new fails and should never be summed; Price is the previous trading day's closing price per SEC convention; the coverage window and partial-coverage caveat; the two-week publication lag; and the interpretation of high/persistent balances. This is exemplary transparency.

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 longer than a simple one-liner, but every sentence earns its place by disclosing a necessary caveat or convention. It starts with a clear purpose statement and then expands with critical usage details. It is well-structured and not bloated, though it could be tightened slightly.

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?

Given there is no output schema, the description fully explains the return semantics: Quantity, Price, Value, coverage windows, missing dates, publication lag, and interpretation. It covers all aspects an agent needs to correctly use the tool and interpret its results, making it highly complete.

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 100%, so the baseline is 3. The description does not directly explain parameters further but adds context about output semantics (e.g., missing dates, lag) that indirectly affects parameter interpretation (e.g., endDate default trails today). This is marginal value, not enough to raise the score.

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 opens with a specific verb and resource: 'Get fails-to-deliver (FTD) data for a stock from the SEC's twice-monthly FTD files.' It clearly differentiates this from siblings like short interest or short volume by focusing on FTD specifically. The scope and source are unambiguous.

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 clear context on when this tool is relevant, noting that 'High or persistent FTD balances may indicate naked short selling or settlement issues.' While it doesn't explicitly name alternative tools or exclude them, the context is sufficient for an agent to infer appropriate use cases. It stops short of explicit when-to-use vs. alternatives guidance, so not a 5.

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