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

Annotations already mark destructiveHint=true and readOnlyHint=false, but the description adds meaningful context beyond them: it does not post to Xero, may require manager approval on first use, and cannot be used by scheduled activities. This gives the agent a richer behavioral model than the flags alone.

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 purpose is front-loaded and the routing and approval guidance are clearly separated into labeled sections. The approval block is somewhat verbose, but every sentence carries actionable information for correct invocation.

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 4-parameter mutation tool with full schema coverage and no output schema, the description covers dependencies, routing, constraints, and approval flow. An agent has everything needed to invoke it correctly in the intended sequence.

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%, so baseline is 3. The description adds important semantics: pass the FreedomOS category name (account), not a Xero code, and obtain transaction_id from list/search calls. This clarifies the account and transaction_id parameters beyond what the schema states.

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 ('Change'), a clear resource ('cash category on one company transaction'), and immediately distinguishes itself from related tools by noting it does not post to Xero. This separates it from post_xero_transaction and set_xero_account_map without needing to open those 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?

It explicitly instructs the agent to call get_transactions or search_transactions first to obtain the transaction_id, and to pair with set_xero_account_map and post_xero_transaction to book the code. It also gives a clear exclusion ('A scheduled activity cannot recode books') and explains the approval workflow, leaving no ambiguity about when and how to use it.

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