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

The annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context: it specifies which fields invalidate the cached estimate, noting it will be refreshed on the next get_portfolio_property call, and states the credit cost. This exceeds what annotations alone convey, though it doesn't detail permission needs or partial-update semantics.

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?

The description is front-loaded with required information, uses clear headings, and efficiently lists optional parameters and the invalidation note without wasteful sentences. Every part serves a purpose.

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 an 11-parameter update tool with annotations covering safety and idempotency, and no output schema, the description provides a complete picture: required vs. optional fields, side effects (cache invalidation), and cost. It could mention whether updates are partial or full-replace, but otherwise is sufficient.

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 description coverage is 100%, so the baseline is 3. The description adds meaning by highlighting the required parameter and listing optional ones, and by calling out the invalidation effect for specific fields. However, it doesn't add syntax or format details beyond what the schema provides.

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 clear verb+resource ('Update metadata for a portfolio property') and lists the mutable fields. It doesn't explicitly differentiate from siblings like add_property_to_portfolio or delete_portfolio_property, but the verb 'update' combined with the field list makes the purpose unambiguous.

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?

The description implies usage by naming required and optional parameters, and the note about cache invalidation provides context for when the operation has side effects. However, it doesn't explicitly state when to use this tool versus alternatives (e.g., delete_portfolio_property or add_property_to_portfolio) or any prerequisites beyond the ID requirement.

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