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

Annotations already declare the mutation/safety profile (readOnly=false, destructive=false, idempotent=false), so the bar is lower. The description adds genuinely new context the annotations cannot express: the destination site must pre-exist, and execution may be gated by configurable org-level MCP approval settings plus mandatory business workflow approvals — important for an agent planning a call sequence.

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 with the core action front-loaded and no filler. The approval sentence is denser than the rest but still carries actionable information rather than boilerplate.

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 return values need no explanation, and the approval/permission nuance is covered. The remaining gap is behavioral: what happens to any budget already on the site (overwrite, merge, or error) is unstated, which matters for a non-idempotent mutation.

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 0% on two required parameters, one of which is a nested object, so the description must compensate. It only implicitly indicates that one identifier is a template and one is a site; it never says that the top-level 'id' is the template ID rather than the site ID, leaving the most likely source of mis-invocation unaddressed.

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 ('Apply a budget template') plus a constraint on the target ('to an existing site'). However, it never distinguishes this from the near-identically named sibling apply_project_budget_template, so an agent cannot tell which one applies to site budgets vs. project budgets from this text alone.

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?

'Does not create the destination' implies the site must already exist, which is a real prerequisite hint. But there is no explicit when-to-use guidance versus clone_budget_template, apply_project_budget_template, or create_site_budget, and no statement of when applying is inappropriate.

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