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

The annotations already declare a safe read (readOnlyHint=true, destructiveHint=false), and the description adds genuinely non-structured context: the record is scoped to the CURRENT USER resolved from their API key, so cross-wallet access is impossible. It does not describe failure behavior for an unknown or foreign transaction id, leaving a small gap for an idempotent=false read.

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 short sentences, front-loaded with the core purpose, then the prerequisite, then the access-scope constraint. Every sentence carries distinct information; nothing is redundant with the title or schema.

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 one-parameter read with full schema coverage, annotations, and an output schema, the description covers purpose, id provenance, list-vs-detail routing, and user scoping. No return-value explanation is needed because the output schema exists.

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 parameter is documented, so the schema does the heavy lifting (baseline 3). The description adds value the schema cannot: the provenance of `transaction_id`, telling the agent to obtain it from `get_my_transactions` rather than construct or guess it.

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 and resource ('One transaction in full detail, by its id') with explicit singular-by-id scope. It is clearly separable from the sibling `get_my_transactions`, whose name is invoked as the source of ids. An agent can distinguish detail-fetch from list-fetch without opening schemas.

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?

Gives an explicit prerequisite ('Get the id from `get_my_transactions` first') and an explicit exclusion ('this tool does not search or list'), which routes the agent to the right sibling for listing. It also rules out a whole class of misuse by stating there is no way to query another wallet.

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