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

Annotations only say readOnlyHint=false and openWorldHint=true; the description adds the substantive behaviors that matter — the free re-export window and the hard immutability constraint on address, center, groundWidthM, pageSize, orientation and dpi. It does not describe what a successful re-export returns, but the mutation semantics are well covered.

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 tight sentences with the verb and the free-window hook front-loaded, then the constraint. Every clause earns its place; no filler or restatement of the title.

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 a 16-parameter, nested-object mutation tool with no output schema, the description carries the essential framing: the required mapId source and the immutability rule. Given the schema already documents the bulk of parameter detail, this is complete enough for correct invocation, though it says nothing about what the revision returns or whether it preserves the original.

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 already high (~75%), but the description adds meaning the schema cannot: it identifies precisely which parameters constitute the frozen 'frame' versus the mutable ones, so the agent knows that passing a new center or pageSize silently makes this a different map. That is real value beyond the per-field descriptions.

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 ('Re-export a map bought with make_map') and immediately scopes it against the purchasing sibling, so an agent can tell this apart from make_map or preview_map without opening a schema. The 'free for 7 days' qualifier further sharpens the purpose.

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 clear when-to-use context: only for an already-bought map, only within a 7-day window, and only when the frame is unchanged. It lists what may change versus what is frozen, which is exactly the decision an agent needs. It stops short of naming preview_map or make_map as explicit alternatives for adjacent cases.

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