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

Annotations already declare readOnlyHint=true, destructiveHint=false and idempotentHint=true, so safety is covered. The description adds genuine behavior beyond that: pagination defaults and max, the at-least-one-filter constraint, and the literal substring-matching semantics with real matching pitfalls ('filler words like refund ... match nothing'). It stops short of describing the response shape or total-count behavior.

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 precondition and pagination facts are front-loaded, and each sentence carries information. It is somewhat long and the search semantics are restated in both the description and the `search` property, which is mild redundancy rather than waste.

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 13-parameter, zero-required read tool with no output schema, the description covers the constraint, filtering model, pagination, and alternatives well enough to call correctly. It does not say what a transaction record contains, which matters slightly more here because there is no output schema to fall back on.

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?

With schema coverage at 100%, a baseline 3 is warranted, but the description goes further on the highest-risk parameter by explaining that search terms are space-separated, ANDed, substring-matched across named fields, with worked examples ('epartner 36' = payee + amount fragment) and a warning against filler words. The remaining parameters are left entirely to the schema.

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+resource ('Lists transactions') plus scope ('with pagination, default 30/page, max 100'), and later distinguishes itself from both get_transaction (single record, implicitly) and navigate_to_transactions. An agent can route correctly without opening the schema.

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 states a hard precondition ('Requires at least one of user_id, account_id, category_id, or transaction_account_id'), an explicit exclusion ('the richer in-app search ... is not available via the API — offer navigate_to_transactions for those'), and names the exact sibling tools to call to obtain each ID. This is when/when-not/alternatives guidance in full.

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