Download transaction attachment

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: the file is written to the download directory with owner-only permissions, the return value is a path, and images are additionally displayed inline.

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 dense, front-loaded sentences with no filler; the core action comes first and the side effects and return behavior follow immediately.

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?

With no output schema, the description correctly carries the return-value burden by stating a path is returned and images are shown inline, and it discloses the on-disk write. What is missing is only the explicit sequencing relationship with list_transaction_attachments, which the schema hints at but the description does not state.

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%, so the schema already documents all five parameters including the account/category defaults and the saveAs path semantics. The description adds no parameter-level detail beyond this, so the baseline 3 applies.

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 states a specific verb and resource ('Downloads a file attached to a transaction') and adds scope details — saves to the download directory, returns the path, renders images inline. It is clearly distinct from list_transaction_attachments, though it never names that sibling explicitly to make the differentiation airtight.

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: the attachment UID parameter notes it comes from list_transaction_attachments, which sketches the workflow. The description itself gives no explicit when-to-use, prerequisites, or when-not-to-use guidance (e.g., use list_transaction_attachments first to discover UIDs).

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