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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and closed-world behavior, so the safety profile is covered. The description adds genuinely useful cross-tool context beyond that: the returned values are not opaque labels but the exact metro_code enum accepted by create_project, which is information annotations cannot convey.

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 sentences, zero waste, front-loaded with the core action and followed immediately by the one fact an agent needs (what the values are used for). Nothing is redundant with the title or annotations.

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?

An output schema exists, so the description is not obliged to enumerate return values. For a simple, parameterless, read-only lookup, the description plus annotations plus output schema give the agent everything needed to select and invoke it correctly.

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 baseline this scores 4. The description correctly adds nothing about parameters, which is appropriate for a no-argument enumeration call.

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 states a specific verb and resource ('List the regional construction pricing markets supported by Portravo') and immediately clarifies the semantic role of the result: they are the accepted metro_code values for create_project. An agent can distinguish this enumeration/lookup tool from siblings like create_project or list_projects without opening any schema.

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?

By tying the output to create_project's metro_code parameter, it strongly implies the usage context (call this to discover valid inputs for project creation). It stops short of an explicit 'use this before calling create_project' instruction or any exclusion, but the context is clear and leaves little to inference.

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