add_contact_to_group

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

With no annotations, the description carries the full burden. It implies a membership mutation but says nothing about idempotency, what happens if the contact is already a member or the group is missing, or what the call returns. The truncation leaves even the scope unresolved.

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 single sentence ends in a truncated word ("...to an existing gro..."), a structural defect rather than true conciseness. The front-loaded purpose is reasonable, but the core object of the sentence is left incomplete.

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 mutation tool with no annotations, no output schema, and an empty parameter schema, the description should clarify required inputs and effects. Instead it names identifiers the schema doesn't expose and cuts off mid-sentence, leaving an agent unable to construct a valid call confidently.

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?

The schema declares zero parameters, which normally gives a baseline of 4. But the description references contact_id, name, and a group that the schema does not expose, creating a mismatch that could mislead the caller about what inputs to provide.

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 uses a specific verb and resource — adding a contact found by contact_id or name to an existing group in Contacts.app. However, it is truncated mid-word ("to an existing gro...") and doesn't distinguish itself from sibling contact/group tools.

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?

No explicit when-to-use guidance or alternatives are given. The phrase "to an existing gro..." implies the group must already exist, but the sentence is cut off before any prerequisite or exclusion can be stated.

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