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

With annotations covering the safety profile (readOnly=false, destructive=false, openWorld=true), the description still adds real value: it discloses the side effect (team-visible record), that nothing is sent to the person, the confirmation policy, and an authentication requirement (Cotlet API key with app access). It omits idempotency/duplicate handling, which keeps it from a 5.

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?

Front-loaded with purpose, then effect, then dedup guidance, then auth. Sentences are dense and mostly earn their place, though the field enumeration in the first sentence mildly duplicates the 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?

No output schema exists, but the description states the return value (contact_id) and covers auth, side effects, and dedup strategy. For a simple 5-parameter create tool with annotations, this is nearly 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 100% with self-describing fields, so the baseline is 3. The description restates the same fields (name, phone, email, mailing address) without adding format rules or noting which two parameters are required (first_name, last_name).

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 (adds/creates) and resource (one contact), and enumerates the fields it carries (name, phone, email, address). It distinguishes itself from find_contact by routing dedup to that sibling, so an agent can tell the two apart.

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?

"Use find_contact first to avoid duplicates" gives an explicit alternative and the condition that selects it, and "runs without asking" clarifies the confirmation posture. It stops short of stating when NOT to use this tool (e.g. updating an existing contact), but the context is clear.

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