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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the description does not need to restate them. It adds valuable context about what Markers are, how they are minted and spent, and that they are never cash, refunded, transferred, or exportable. This goes beyond the structured annotations and helps an agent understand the domain semantics.

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 front-loaded with the main purpose and then gives compact, relevant background on the Marker system. Every sentence adds context about what the values mean or how the currency behaves. It could trim the parenthetical details slightly, but it remains readable and efficient.

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 tool has no required parameters and no output schema, so the description needs to convey what calling it will return, which it does: balance, history, and prices. It also includes relevant eligibility and economic constraints. The only minor gap is not describing the return shape in more detail, but for an optional-parameter read-only query this is adequate.

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%: both `limit` and `api_key` are already described in the input schema with constraints and defaults. The description adds nothing about the parameters, but the baseline of 3 applies because the schema fully documents them.

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 first sentence clearly identifies the tool's subject: 'Your Marker balance and history, and the prices.' It goes beyond the name by specifying that it returns balance, history, and pricing, which distinguishes it from general ledger or transaction tools. It does not explicitly contrast a sibling tool, but the resource is specific enough that the purpose is 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 implies that this tool is for viewing Marker balance, history, and prices, and it adds membership eligibility context. However, it does not explicitly state when to prefer this over similar financial tools like continental_ledger, nor does it give any 'use this when' or 'use that instead' guidance.

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