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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds real value beyond them: the immutability of the parent asset, the business invariant that the row must still contribute capital or life after the update, and the required asset_betterments:write scope.

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?

Three short sentences, front-loaded with the action and ID, then constraints and permissions. Every sentence carries distinct information with no repetition of 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 covers the mutation semantics, the key invariant, immutability rules, and the auth scope. It does not state response shape or whether non-mentioned fields are preserved, which is a minor gap for a tool whose full parameter set is already fully documented in the schema.

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 exceeds that by stating a cross-parameter constraint absent from the schema: the row must still add either capital or life after the update, which effectively governs capitalized_amount and added_life_years together.

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 ('Update a betterment by ID'), which pins it precisely against siblings like create_asset_betterment, delete_asset_betterment, and list_asset_betterments within a very large CRUD family.

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?

Gives a clear when-to-use context (updating an existing betterment by ID) and notably routes around an unsupported case: 'The asset it belongs to cannot be changed - delete and re-create to move one.' It does not enumerate alternative tools by name, but the delete/re-create guidance functions as de facto routing.

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