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

Annotations already establish readOnlyHint=true and idempotentHint=true, so the read-only nature is covered. The description adds meaningful behavioral nuance: 'the full oracle state never treats partial evidence as CALM' exposes a domain rule about evidence handling, and the compatibility note about the retained peg/run alert clarifies the tool's relationship to older endpoints. It also includes a disclaimer that the board is not investment advice. These go beyond the structured hints.

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 three sentences: the first defines the board's content, the second points to a more detailed route, and the third covers arguments, behavioral rules, and a disclaimer. There is no wasted wording; every clause serves a distinct purpose, and the main verb+object is front-loaded.

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?

The board is complex, and the description covers its key facets without an output schema. It enumerates the tracked evidence categories, states that full data is available on the REST route, clarifies no arguments are expected, and discloses a behavioral rule about CALM. This is sufficient for an agent to decide whether to call the tool and what to expect.

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?

With zero parameters, the schema has full coverage and nothing to explain. The description explicitly states 'Takes no arguments,' which removes any ambiguity about invocation. This is the expected baseline for a no-parameter tool and adds just enough clarity.

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 'Read' and clearly identifies the resource as the 'Stablecoin Rails board.' It then enumerates the board's distinct scope—peg, redemption-run, liability validation, reserve evidence, chain concentration, tripwire state, and aggregate regime—which differentiates it from sibling boards like crypto_exposure_board or household_credit_board. This is a precise and non-generic purpose statement.

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 context on when to use this tool: it is a compact read-only board, while 'Series and full receipts stay on the public REST detail route' signals that granular data is served elsewhere. It also notes that the separate peg/run alert is retained for compatibility, implying this board is an aggregate view. However, it does not explicitly name or contrast sibling tools, so it falls just short of a 5.

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