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

Annotations already cover read-only safety, but the description adds substantial beyond-schema context: what the payload contains ('never rupee amounts and never an owner's name'), the meaning of null parent_cost_centre_id, and the operational semantics of is_active=false as DEACTIVATED. It doesn't mention pagination behavior beyond the schema, but the disclosure load is well carried.

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-loaded with purpose and sequencing, which is good, but the description is long and mixes operational rules ('never count it when you tell the user how many targets exist') with instructional guidance that borders on over-prescription. Most sentences earn their place, but a tighter version would read better.

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, and the description fills that gap by describing the returned fields and their hierarchy meaning, plus the is_active caveat. It doesn't spell out pagination/truncation behavior, which matters for a list tool, but overall an agent has what it needs.

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 coverage is 100% with clear param descriptions, so the baseline is 3. The description adds no per-parameter detail (e.g., how page interacts with large hierarchies) that the schema doesn't already supply.

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+resource ('List the cost centres for an entity') and immediately distinguishes itself from siblings like list_profit_centres and create_cost_centre by tying its role to mapping proposals and code selection.

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 explicit sequencing ('Use this before proposing account mappings', 'Check the returned codes before choosing a code for create_cost_centre') and hard exclusions ('never propose a mapping onto a deactivated centre'). The when-to-use against create_cost_centre is unambiguous.

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