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

Annotations already mark the tool as read-only and idempotent. The description adds significant behavioral context: it explains the error response structure (returns {total, results, warning} instead of throwing), the data integrity cross-checking mechanism, and the integrity flag for suspect zeroed rows. This goes well beyond 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 well-structured with clear sections, front-loads the main purpose, and is appropriately detailed for the tool's complexity. However, it could be slightly more concise.

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?

Despite no output schema, the description thoroughly explains the response structure (total, results, warning, data_integrity_warning) and the fields within each row (balance, amount, rates, etc.). It also covers error handling for disabled product and data integrity edge cases. This makes the description highly complete.

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 input schema has 6 parameters with no descriptions, and the description only explicitly mentions the item_ids parameter for bulk support. It does not explain the meaning of item, page, type, page_size, etc. With 0% schema coverage, the description should compensate but fails to do so.

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 explicitly states that the tool returns the investment portfolio for a connection, listing specific asset types (FIIs, stocks, ETFs, etc.). This clearly distinguishes it from sibling tools like list_accounts or list_transactions.

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 explicitly tell when to use this tool versus alternatives like list_investment_transactions. It mentions error handling and bulk support, but lacks guidance on use cases or exclusions.

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