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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds concrete substance: replacement semantics per field, the partial-update guarantee ('Only the fields you pass change'), and an explicit confirm-with-user-before-writing caution. It stops short of covering failure modes or what the response returns, which keeps it at 4 rather than 5.

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 sentences, all front-loaded: trigger first, then the destructive-replacement warning, then the partial-update rule, then the sibling redirect. No sentence is filler and the ordering matches the agent's decision sequence.

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, zero-required mutation tool with annotations but no output schema, the description covers purpose, triggers, replacement behavior, and the sibling alternative. It leaves open what happens when the named brand doesn't exist and what the response looks like, which is a minor gap given the schema carries the per-field and brand-selection guidance.

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% and every parameter already has a documented meaning, so the baseline is 3. The description echoes the field list and clarifies that unspecified fields are untouched, which is mildly useful but adds no format or validation guidance beyond the schema.

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 set (rename, set, replace) against a named resource (brand) and enumerates the exact identity fields in scope. The agent can distinguish it from get_brand, create_brand, and remember_brand_fact without opening any schema.

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?

Opens with an explicit trigger ('when the user asks to rename a brand or to set or replace its core identity') and names the alternative for the adjacent case: 'For adding a short fact without replacing anything, use remember_brand_fact instead.' Both when-to-use and when-to-use-something-else are stated.

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