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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new context: that inputs are auto-detected from links, emails, owner/repos, or notes. It does not describe the result of a successful add or how ordering interacts with 'after'.

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?

A single tightly packed sentence with the verb front-loaded and the parameter guidance following immediately. Every clause carries information and nothing is padded.

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 6-parameter mutation tool with a nested tile object and no output schema, the description covers only the content-input parameters. It says nothing about size, color, or after placement, and does not indicate what is returned, leaving several parameters unaddressed in both description and 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 coverage is 67% and the description meaningfully complements it, clarifying that inputs (plural) takes several values, input takes one, and both are auto-detected while tile expects a full object. This resolves the mutually-exclusive input modes better than the schema alone.

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 ('Add tiles'), which clearly distinguishes it from move_tile, remove_tile, and update_tile in the sibling set. It stops short of explicitly framing itself as the creation counterpart to those tools, so it is clear but not maximally differentiated.

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?

It explains the three ways to supply content (inputs, input, or a tile object), which is actionable invocation guidance, but never says when to reach for add_tile versus siblings like import_page or update_tile. Usage is implied rather than scoped.

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