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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safe-read nature is covered. The description adds details about supported filters and bulk execution, which is useful. However, it does not clarify pagination behavior, response format, or potential errors. It does not contradict annotations.

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 verbose and includes a full list of actions that belong to other tools, making it messy. The '[Flattened action: by_marketplace]' note is buried. It could be trimmed to a few sentences focusing on the by_marketplace functionality and its specific parameters. Structure lacks clarity and front-loads irrelevant info.

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?

With 20 parameters and no output schema, the description should explain the tool's purpose, how marketplace_name/marketplace_id interact, what 'sub' returns, and what the response looks like. It does not. The mention of bulk support is beneficial, but the overall context is incomplete and confusing due to listing unrelated actions.

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 0%, so the description must compensate. It does provide meaning for some parameters: date formats (YYYY-MM-DD), sub enum values (detail|activities|order-bumps|etickets), and mentions marketplace_name/marketplace_id. However, it omits many parameters like ids, account, product_ids, and subscription_ids, and does not explain their purpose. Partial compensation only.

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 starts with a broad statement about Guru sales/transactions and lists multiple actions (search, get, activities, etc.) without clearly indicating that this tool is specifically for by_marketplace. The phrase '[Flattened action: by_marketplace]' suggests it is only for that action, but the description's broad list obscures that. A specific verb+resource like 'Retrieve transactions filtered by marketplace' would be clearer.

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?

No explicit guidance on when to use this tool versus the many sibling tools (guru_transactions_search, guru_transactions_get, etc.). The description mentions multiple actions, which could mislead an agent into thinking this handles all those scenarios. It does not state 'Use this for marketplace-specific queries, not for general search.'

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