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

Annotations already convey mutation (readOnlyHint=false), non-idempotency, and non-destructiveness, so the description's 'Change' adds limited new behavioral signal. It does add useful scope context by saying what it does not affect, but it does not disclose asynchronous behavior, side effects, or consequences beyond the annotation data.

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?

Two sentences, zero filler. The primary action is front-loaded, and the second sentence efficiently provides the exclusion and alternative routing. Every clause earns its place.

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 10-parameter mutation tool, the description gives a clear core purpose and boundaries, while the schema's detailed descriptions cover throttling, polling, and completion behavior. It omits mention of subType and asynchronous completion semantics, but those are adequately handled in the structured schema, so the overall context is strong.

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 baseline is 3. The description summarizes memo, tags, and operationType, which helps frame the main editable parameters, but it largely restates information already present in the schema and does not add deep meaning for subType, polling, or timeout parameters.

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 names a specific verb and resource ('Change one accounting transaction's memo, full tag set, or operation type') and clearly distinguishes the tool from the closest sibling by stating what it does NOT change. An agent can confidently identify this as the tool for editing transaction-level fields without confusing it with update_journal_entry_line.

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?

The description explicitly states the exclusions ('does not change ledger accounts, counterparties, or reporting-group assignments') and directly names the alternative tool to use for those cases ('use update_journal_entry_line for those'). This is an explicit when-not/alternative pairing, leaving little ambiguity.

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