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

With no annotations, the description carries the full burden and does reasonably well: it discloses partial-update behavior and the automatic holding recalculation side effect after every update. It omits permissions/auth requirements and whether changes are reversible, keeping it short of a 5.

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 tight sentences, front-loaded with the action, followed by the ID source and the update side effect. No filler or redundancy.

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 annotations and no output schema, the description covers what is changed, where the ID comes from, and the recalculating side effect. It leaves the response shape and failure/validation behavior unaddressed, but nothing critical to invoking it correctly 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?

Schema description coverage is 100%, so the schema already documents every field's type and format. The description's field list adds only high-level confirmation of what is editable and does not clarify formats, decimal-string semantics, or category enum meaning beyond 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?

States a specific verb+resource ('Update an existing investment transaction') and enumerates the mutable fields (date, quantity, price, fees, category, label). The 'investment' qualifier cleanly distinguishes it from the generic update_transaction sibling, so an agent can route 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?

Explicitly names get_investment_transactions as the source of the required transactionId, which is the key precondition. It also clarifies patch semantics ('Only provided fields are changed'), though it offers no when-not guidance or named alternative for related edits.

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