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

The annotations already flag destructiveHint=true and idempotentHint=false, so the safety profile is carried by structured data and the description does not contradict it. The description adds only that the operation spans many contacts by id; it omits whether deletes are irreversible, how partial failures across a batch are handled, and any confirmation requirements.

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?

A single front-loaded sentence that enumerates the three actions with zero filler. It is terse to the point of leaving information gaps, but nothing in it is redundant.

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?

There is no output schema and no nested objects, so the return-value burden is low, but this is a destructive bulk mutation over up to 500 records and the description says nothing about irreversibility, partial-success semantics, or rate/scale constraints. Annotations cover the safety hint, leaving the description adequate but not complete.

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 coverage is low at 33% (only 'tags' is documented), so the description should compensate but does not. It does map its three verbs onto the action enum and states that ids are the targeting mechanism, but it never mentions the 500-id maximum, the 40-character tag limit, or that tags is mandatory for the two tag actions beyond what the schema already says.

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 names a specific verb set (add tags, remove tags, delete) against a specific resource (contacts) with a stated scale ('many... by id'), so an agent can tell it apart from the single-record siblings update_contact and delete_contact. It stops short of naming those siblings explicitly, so it is clear but not fully differentiated.

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?

'many contacts by id' implies this is the bulk alternative to delete_contact/update_contact, which is useful implied guidance. However, there is no explicit statement of when to prefer this tool, no warning that the 'delete' action is permanent and cannot be undone, and no guidance on batching limits or failure handling.

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