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

Annotations declare readOnlyHint=false, openWorldHint=true, destructiveHint=false — a mutating, network-touching but non-destructive call. The description adds the key consequence the annotations cannot convey: this SPENDS the user's coins, and the expected_cost must match what the person actually saw on the button. That is genuinely useful spend-safety context, though retry/idempotency behavior is only covered in the schema, not the description.

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 short sentences, front-loaded with the scoping constraint before the cost warning. Slight waste in restating the title ('upscale from the app:'), but no filler beyond that.

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?

Has an output schema and 100% parameter coverage, so return values and argument formats need no prose. The description supplies exactly the two things structured fields can't: platform scope and the fact that coins are spent at a user-visible price.

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%, so the baseline is 3. The description still earns above baseline by pinning expected_cost to 'the number on the button the person pressed', which is a semantic anchor the schema's 'the coins estimate_upscale answered' does not fully capture in UI terms. Other parameters are left entirely to the schema.

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 ('upscale from the app') and immediately scopes it: 'For the Veltake app's own screens only — not for a conversation.' That implicitly separates it from the conversation-level `upscale` sibling, though it never names that sibling or `app_upscale_quote`, so the differentiation is inferred rather than explicit.

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 (app's own screens) and when-not (not for a conversation). The prerequisite estimate step is only implied via 'expected_cost, the number on the button the person pressed' and the schema's 'as passed to estimate_upscale'; the description never tells the agent to call app_upscale_quote first.

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