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

Annotations already declare read-only, idempotent, non-destructive and open-world, so the safety profile is covered. On top of that the description discloses provenance (New York Fed), cost (1 credit), the exact dimensions/breakdown of the returned data, and interpretive context for the headline figure — genuinely additive rather than restated annotation.

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?

Front-loaded with what the tool returns, then scope exclusions, then interpretation, then cost — every clause carries information. Despite being a fairly dense sentence chain there is no filler and nothing repeated from the schema or annotations.

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?

No output schema exists, but the description compensates by enumerating the result fields (submitted/accepted amounts, collateral split, offering rate) and the source. For a single-optional-parameter read tool with full annotations, nothing an agent needs before calling 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?

Schema description coverage is 100%, so the single parameter (last_n, 1-50, default 5) is already fully documented in structured data. The description adds no further constraint or semantics for it, so the baseline 3 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?

Names a specific resource (Fed Standing Repo Facility operations results) and states exactly what the payload contains: submitted vs. accepted amounts, split by collateral type, with the offering rate. It also explicitly carves out what it is not (forward schedule, reverse repo), so an agent can distinguish it from adjacent tools at a glance.

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 a real when-to-use signal — 'take-up is the headline sign of month- and quarter-end funding stress' — and explicit when-not-to-use exclusions for the forward schedule and reverse repo. It stops short of naming the sibling tools, so the agent must map 'its own tool' to a concrete name itself.

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