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

Annotations only indicate the call is neither read-only nor destructive. The description adds the key behavioral trait that a session is created and must precede all other IBK fast-account calls, but it stops short of explaining session state, expiry, or side effects. This adds value without being rich behavioral context.

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?

Two short, direct sentences with no filler. The most important operational instruction ('Call this FIRST') is front-loaded, and every phrase earns its place.

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 tool with one optional, fully documented parameter and no output schema, the description provides enough context: it names the session, the provider, and the required call order. The only minor gap is the undefined phrase 'parent account link,' but the schema's account_link_id description covers that concept.

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 already fully documents account_link_id, including optionality, server-side auto-resolution, the multi-certificate caveat, and per-institution ID separation. The description's 'parent account link' phrase merely echoes the schema, adding no new parameter-level meaning.

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 uses a specific verb ('Create') and names the exact resource: an IBK fast-account session. The provider qualifier 'IBK' and the parent-account-link source distinguish it from sibling session-login tools like kb_fast_account__session__login and hometax__session__login.

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?

'Call this FIRST before any other tool for this provider' is an explicit when-to-use directive: it is the required bootstrap for all IBK fast-account tools. It does not enumerate exclusions or alternatives, but provider scoping and ordering are clear.

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