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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the login prerequisite and the scope ('balance and daily summary'), which are behavioral details not in the annotations. There is no contradiction. It does not mention error behavior or output format, but for a read-only tool with annotations, this is acceptable.

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 two sentences, front-loaded with the critical prerequisite, and contains zero fluff. Every word adds value: the login requirement, the same-link condition, and the exact output scope. It is exemplary in structure.

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 simple read operation with annotations covering safety and no output schema, the description is nearly complete: it tells what it does, when to use it, and the key prerequisite. The missing piece is guidance on the optional parameters, but those are largely auto-resolved or system-driven, so the gap is minor. Overall it is sufficiently complete for an agent to call it correctly in most cases.

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 only 25%, meaning most parameters lack descriptions. The tool description does not explain any parameter beyond the implicit 'account_link_id' mentioned in the prerequisite. It does not compensate for the low coverage, leaving the agent to rely on the schema alone, which is insufficient for optional parameters like bank_account_credential_ids and bank_account_selection_mode.

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 ('Read'), a concrete resource ('balance and daily summary for one registered IBK bank account'), and is clearly distinguished from sibling tools like transaction-history or login tools. It names the exact institution (IBK) and the operation scope, leaving no ambiguity about what this tool returns.

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 states a required prerequisite: a prior ibk_fast_account__session__login call with the same account_link_id. This tells the agent when it can be used and the condition (same link ID). It does not name alternatives, but the context of sibling tools makes it clear that this is the only quick-summary tool for IBK, so the usage context is adequately conveyed.

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