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

With no annotations, the description carries the full burden and does so well: it discloses the destructive cascade (deletes the portfolio transfer, reverses the cash balance change, restores the transaction type) and the idempotent-like behavior ('Succeeds even if the transaction has no portfolio link'). These are exactly the behavioral traits an agent needs before invoking a mutation.

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?

One sentence of purpose followed by a colon and a tight list of side effects, then a single clause on the no-op case. It is front-loaded and wastes no words, though it could be marginally tighter.

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 single-parameter mutation tool with no annotations and no output schema, the description covers what the tool does, its side effects, and its behavior when the precondition is unmet. An agent has everything needed to call it correctly.

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 coverage is 100% and the single UUID parameter is fully documented in the schema. The description adds the constraint that the ID refers to a transaction 'currently linked to a portfolio', which subtly qualifies the parameter's expected state beyond the schema's generic description. Still, with zero description of parameter handling in the prose, it stays just above baseline.

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+resource ('Remove the portfolio link from a transaction') and immediately enumerates the three concrete side effects. It is clearly distinguishable from sibling link_transaction_to_portfolio (the inverse) and unlink_transfer.

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 describes the operation's context and clarifies it succeeds even when no link exists, which removes ambiguity about preconditions. It does not, however, name alternatives or explicitly state when to prefer this over manually updating the transaction.

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