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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond them by disclosing the returned fields (name, number, type, currency, current and starting balance) and the parent/child data model, which is exactly the behavioral context annotations cannot convey.

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?

Front-loaded with the action and identifier, followed by two short sentences of domain context and one listing return fields. Every sentence carries information, though the entity-model explanation is slightly more than strictly required for a single-parameter lookup.

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, and the description compensates by enumerating the returned fields, so an agent knows what a successful call yields. It omits error behavior (e.g., unknown ID) and the sibling routing question, which keeps it below 5 for a tool in such a crowded namespace.

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 100% for the single 'id' parameter, so the baseline is 3. The description restates that lookup is by ID but adds no format, range, or failure semantics beyond what the schema already says.

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 opens with a specific verb and resource ('Gets a transaction account by its ID') and defines the domain entity, including its relationship to a parent account and institution. It stops short of distinguishing itself from nearby siblings like get_account or list_transaction_accounts, which an agent would have to infer from names alone.

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?

Usage is only implied by 'by its ID'. There is no statement of when to use this instead of get_account, list_transaction_accounts, or get_institution, and no prerequisites or exclusions are given, despite several look-alike siblings in the toolset.

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