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

With no annotations, the description must carry the behavioral burden, and it partly does: the verb 'Get' signals a read operation and the parenthetical discloses units (basis points) and the nature of the content. It does not state freshness/caching, whether the attribution covers only top contributors or the full index, or any auth or rate-limit constraints.

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?

A single sentence with the resource and time window front-loaded, and the parenthetical earns its place by decoding what 'attribution' returns and in what unit. Nothing is redundant or padded.

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?

For a zero-argument, no-output-schema tool the description covers the essentials: what it fetches, the time period, the unit, and the conceptual return shape. It stops short of describing the return structure (ranked list, sign convention, number of contributors), which is the one thing an agent cannot recover from the empty schema.

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 there is nothing for the description to disambiguate beyond what the empty schema already shows. Baseline 4 applies; no parameter meaning is missing.

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 pairs a specific verb ('Get') with a specific resource ('this week's index change attribution') and clarifies the payload with a parenthetical ('which bonds moved the index, in bp'). That distinguishes it in substance from siblings like ncsx_levels or ncsx_constituents, though it never names those siblings to route the agent explicitly.

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?

Usage is only implied: 'this week's' fixes the time window to the current week, so an agent knows the scope without supplying arguments. There is no explicit statement of when to prefer this over ncsx_weekly, ncsx_levels, or ncsx_bond, and no exclusions or prerequisites are given.

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