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

Annotations already cover read-only and idempotent hints. The description adds that the tool supports bulk operations via 'ids' and 'product_ids' and mentions a 'flattened action: transactions', which are not in annotations. However, it does not elaborate on potential side effects or behavior nuances beyond these brief notes.

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 a compact list of actions and parameters, but it uses dense notation with slashes and parentheses that can be hard to parse. It is not overly long, but the structure could be clearer, especially the 'flattened action' and bulk support notes.

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?

Given the tool's complexity (multiple actions, many parameters), the description covers the main operations and filters but omits details about return structures or edge cases. It also fails to explain what 'flattened action' means or how bulk support works exactly. It is adequate for a basic understanding but not fully comprehensive.

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 schema has 15 parameters with zero descriptions, but the description provides some semantics by listing filter parameters (e.g., subscription_status, product_id, contact_email/contact_doc/contact_name, started_at_ini/end, last_status_ini/end, cursor) and action-specific parameters (id for get, invoice_code for invoice/invoice_transactions). However, not all parameters (e.g., account, ids) are explained, and the descriptions are terse and embedded in action lists.

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 'Assinaturas no Guru (leitura)', clearly indicating a read-only tool for subscription transactions. It lists specific actions (search, get, etc.), which distinguishes it from sibling tools like guru_subscriptions_get or guru_transactions_search.

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 does not provide explicit guidance on when to use this tool over alternatives. It lists actions but lacks context on scenarios, such as when to prefer this over guru_transactions_search or guru_subscriptions_invoices. No advice on filtering or bulk usage is given beyond a brief mention of bulk support.

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