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

Annotations flag destructiveHint=true but the description goes far beyond that: it explains the shared-rate blast radius across every tax group, that perOutlet REPLACES the stored list whole and omitted outlets stop charging, and that past sales, receipts and reports are not recalculated. This is exactly the blast-radius detail an agent needs before a destructive call.

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 every sentence carries a consequence for calling the tool, though the perOutlet replacement warning is stated twice (prose and schema) and the all-caps emphasis is slightly heavy. Dense rather than wasteful, but not maximally tight.

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 no output schema, the description still covers everything needed to call safely: identifier source, sharing blast radius, destructive replacement semantics, confirmation requirement, and the retroactivity boundary. Nothing material is missing for a 4-parameter destructive tool.

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 the baseline is 3, but the description adds real meaning: 'percentage sets the same value at every outlet' clarifies how the scalar interacts with the array, and the perOutlet guidance tells the agent to read current values back and resend every outlet that should keep charging. That procedural semantics is not derivable from the schema alone.

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 ('Change a tax rate's name or its percentage') and immediately scopes the identifier source ('takes the tax rate id from get_taxes, never a name'). It also explicitly distinguishes itself from the create_tax_rate sibling when only one group was intended.

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 precondition ('Call get_taxes first'), a required confirmation step ('tell them exactly which groups are affected, and get an explicit yes'), and names the alternative tool with the condition that selects it ('If they only meant one group, the answer is a separate rate via create_tax_rate').

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