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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and the description does not contradict them. The description adds one piece of real behavioral context (unknown custom field codes will be rejected), but it omits duplicate-name behavior and confirmation of what is returned, so with annotations carrying the safety profile a 3 fits.

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 short sentences, core action front-loaded, prerequisite second. Nothing is padded, though the second sentence duplicates schema guidance rather than adding to it.

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 mutating create tool with a nested-object parameter, the description is adequate but thin: output schema exists so return values need not be explained, but duplicate handling, required permissions, and how the tool relates to list/create siblings are missing.

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 every parameter (including the nested custom_fields object and its field-code rules) is already documented in the schema. The description's mention of crm-schema merely restates what the custom_fields schema text says, adding no new syntax or format detail.

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 ("Create a new company in the CRM"), which cleanly separates it from create_people_tool, create_opportunity_tool and the like by entity type. It adds only the CRM context beyond the name, but for a CRUD create tool that is enough to identify it.

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 gives one real prerequisite — read the crm-schema resource to discover custom fields — which is actionable. It says nothing about when to prefer this over update-company-tool, or how to handle an existing company (dedupe path), so guidance is implied rather than complete.

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