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

readOnlyHint=true already establishes this as a safe read. The description adds real behavioral context beyond annotations: the account requirement and the concrete authentication step ('/mcp → Authenticate, then call this tool again'), plus the warning that start_login won't unblock it. It stops short of describing return shape 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?

Front-loads the purpose in the first sentence, then adds a clearly separated access note. Both sentences earn their place, though the access paragraph is slightly verbose for a zero-parameter read tool.

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 zero-param, read-only list tool with no output schema, the description covers purpose and the authentication prerequisite well. Return format is not described, but with no output schema the burden is light and the definition is largely 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?

The tool takes zero parameters, so per the rubric the baseline is 4. There is nothing for the description to clarify on the input side, and schema coverage is 100%.

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 and resource ('Get all default message templates') and clarifies what 'default' means: built-in templates sent when no custom template exists. This implicitly distinguishes it from custom-template siblings like get_template/list_templates, but does not name an alternative explicitly, so it falls short of a 5.

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?

Provides useful access context ('needs a Proof account') and a routing note that start_login does NOT open this tool, but gives no explicit when-to-use-vs-alternatives guidance relative to list_templates or get_template. Usage is only implied.

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