contacts_create

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

Annotations already declare write (readOnlyHint=false), idempotent (idempotentHint=true), non-destructive, and open-world behavior, so the safety profile is covered. The description adds useful context beyond that — the write lands in the 'default writable container' and requires the 'contacts' permission — but does not explain what an existing duplicate does or how the idempotency key behaves.

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?

Extremely compact: a single front-loaded purpose clause plus a bracketed metadata tag. No filler, and the verb+resource leads. The bracket tag is slightly cryptic but does not bloat the text.

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 simple create tool, the description covers purpose, target container, and the governing permission, while annotations cover safety and an output schema covers return values. Little an agent needs is missing beyond optional usage routing toward contacts_update.

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 all six parameters (including givenName, _idempotencyKey, and _approvalId) are already documented in the schema. The description adds no field-level meaning beyond what the schema provides, so the baseline of 3 applies.

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 states a specific verb (Create) and resource (a contact), and narrows the target with 'in the default writable container'. It distinguishes itself from the read-oriented siblings (contacts_get, contacts_search) and the mutating contacts_update by virtue of being the sole create operation.

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 only implied: 'Create a contact' tells the agent what to do but gives no explicit when-to-use condition, no prerequisites, and no reference to alternatives such as contacts_update. The 'permissions: contacts' tag hints at an auth requirement but does not spell out the trigger conditions.

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