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

Annotations already declare the safety profile (idempotentHint=true, destructiveHint=false, readOnlyHint=false). The description adds meaningful context beyond that: it requires an API key, and passing set mutates the default, while omission performs a read. It stops short of describing the response payload, but no output schema exists to cover that.

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 purpose and venue list are front-loaded, followed by the read/write mechanic and auth requirement. It is a single dense paragraph with mild redundancy between the prose and the schema param description, but no wasted sentences.

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 one-parameter, no-output-schema tool, the description covers everything needed: what it shows, the enumerated venues, the read/write behavior of set, and the API key requirement. Nothing an agent needs to call it correctly 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 'set' parameter is already fully documented ('Omit to read. A venue key from the list, or "marginpad" to reset.'). The description largely repeats this (venue key or "marginpad" for default/reset), adding no syntax or format detail beyond the schema, 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?

The description states a specific verb+resource: it lists modeled venues with taker rates and referral discounts, and shows/changes the current default fee schedule. This is clearly distinguishable from siblings like paper_accounts or paper_realism, and an agent can tell exactly what the tool returns and mutates.

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?

It explicitly explains the read-vs-write condition: 'Pass set to change the default' versus omitting it to read. That is clear operational guidance, though it names no sibling alternatives or when-not-to-use conditions.

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