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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=true, so the safety profile is covered. The description adds genuine context by clarifying the operation is purely additive ('without removing existing ones'), but says nothing about failure behavior — e.g., whether an invalid ID aborts the whole call, or whether repeat calls duplicate links.

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, zero filler, with the operation and its non-destructive scope front-loaded. Nothing is repeated from the title or schema.

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 an output schema present and all parameters documented, the definition is callable as-is. What is missing is behavior under partial failure or mixed entity-type batches, which matters for a multi-target relationship mutation, and any pointer to the detach counterpart for reversing the change.

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 each parameter's meaning is already documented in the schema. The description only restates the three target entity categories and adds no extra semantics, such as whether all three lists can be supplied in one call or how duplicates are handled — baseline 3 is appropriate.

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 (attach) and resource (note) plus the three supported target entity types (companies, people, opportunities). The clause 'Adds links without removing existing ones' implicitly separates it from the sibling detach-note-from-entities-tool, though the alternative is never named directly.

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?

Usage is implied: attach instead of detach, and additive rather than replacing. But there is no explicit 'use this when...' guidance, no mention of detach-note-from-entities-tool or update-note-tool as alternatives, and no stated preconditions (e.g., the note must already exist, IDs must be valid).

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