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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds behavioral context the annotations cannot: the presence of a `warnings` array for banks that failed to contribute, including reconnect_url for reconnection cases, which is exactly the kind of failure-mode disclosure an agent needs.

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?

Three sentences, front-loaded with what is listed, then the id contract, then the warnings caveat. No filler and no repetition of the title or annotations.

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?

There is no output schema, so the description has to carry return-value shape itself, and it does: account types, balances, credit limits, institution, last 4 digits, plus the warnings/reconnect_url structure. Nothing an agent needs to call this correctly or interpret the result is missing.

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 tool takes zero parameters, so the baseline is 4. The description still earns that baseline by explaining how the returned `id` value feeds the account_id parameter of sibling tools, which is the only parameter semantics relevant here.

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?

States a specific verb and resource ('List every connected account') and enumerates what comes back (balances, credit limits, institution, last 4 digits), so the agent knows exactly what it gets. The plural 'every connected account' clearly separates it from the singular get_account sibling.

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?

Explains the downstream contract clearly: each account's id is what the account_id parameter of other tools accepts, which tells the agent this is the discovery step before per-account calls. It never explicitly says when to prefer get_account over this list, so the alternative is only implied by the plural framing.

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