team_contacts

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

The description discloses a genuinely non-obvious behavioral trait: emails or phones come back null when Planning Center hides a person's details, i.e. partial results are expected. That adds real value beyond readOnlyHint/openWorldHint, though it says nothing about auth requirements or pagination.

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, front-loaded with the return payload followed by the null caveat. Slightly awkward phrasing ('emails or phones is null') but every sentence earns its place.

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 read-only tool with no output schema, the description does convey what comes back and the null case. However, with two required, undocumented parameters, an agent still lacks enough to construct a correct call.

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?

Both parameters (plan_id, service_type_id) have 0% schema description coverage and no enum values, and the description says only 'one of your plans' without explaining what either id refers to or how to obtain them. The description fails to compensate for the coverage gap.

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 the resource ('email addresses and phone numbers for the people on one of your plans') clearly enough that an agent knows this retrieves contact data for a plan. It does not distinguish itself from the sibling contact_info, so nothing tells the agent why to pick this one.

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?

There is no statement of when to use this versus contact_info or plan_team, no prerequisites beyond the implied required ids, and no exclusions. Usage can only be inferred from the noun phrase.

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