qb_check_duplicate

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

Annotations already set readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds real behavioral context beyond that — that it scans the whole company file, that matching is fuzzy in time because banks don't post both sides on the same date, and which transaction types are scanned by default. Return shape is carried by the output schema, so no gap there.

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 core behavior leads the sentence and the usage directive follows; every clause is doing work. Slightly long due to two parentheticals, but they explain the non-obvious tolerance rationale rather than padding.

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 annotations covering the read-only profile and an output schema covering return values, the description supplies the remaining decision-relevant context: when to call it, what window it searches, and default transaction types. The one hole is the `account` filter, whose effect on results is left entirely unexplained.

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 carry parameter meaning. It covers the two required params (date, amount) and implicitly the tolerance param ('within a tolerance window'), and enumerates the default txn_types values. However, the `account` parameter is never mentioned, nor is the number-or-string flexibility of `amount`, leaving a meaningful gap.

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 ('checks whether a transaction with this date+amount already exists') plus the scope ('somewhere in the company file, within a tolerance window'). The duplicate-detection purpose is inherently distinct from siblings like qb_find_transactions or qb_query_transactions, though none are named explicitly.

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 trigger: 'Use this before posting anything, to avoid double-entry', and highlights the highest-risk case ('especially for payments/transfers, where the same real-world event can get recorded from either side'). It doesn't name an alternative tool or state when not to use it, which keeps it below a 5.

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