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

Annotations already indicate this is not read-only, not idempotent, and not destructive, so the description adds modest context by explaining the update mechanism. However, it does not disclose return behavior, error cases, or what 'passthrough' means, leaving some behavioral ambiguity.

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 a single concise sentence that front-loads the action and resource, then adds the essential input guidance. No words are wasted.

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 mutation tool with no output schema, no parameter descriptions, and a vague 'passthrough' mechanism, the description is too sparse. It lacks details about how filter/changes are structured, whether updates are partial or full replacements, and what happens with invalid or empty inputs.

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 0%, so the description must compensate. It partially clarifies that 'filter' holds target ids and 'changes' holds fields to alter, but it ignores the 'ids' parameter and leaves 'passthrough' undefined. This is insufficient for an agent to confidently construct valid calls.

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 clearly states the action ('Atualiza') and resource ('transações existentes'), and specifies the scope ('uma ou mais'). This distinguishes it from sibling tools like poupa_add_transactions, poupa_retrieve_transactions, and poupa_delete_transactions_by_filter.

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?

The description gives direct usage guidance: put target ids in the filter and provide fields to change via passthrough. It does not explicitly name alternatives or exclusions, but the purpose statement makes the use case clear.

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