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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds genuinely non-obvious context: these documents are also served as MCP resources and this tool is the fallback path. Return format is not described, but an output schema exists to carry that.

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 the core action, then prerequisites, then per-guide content — a sensible ordering with no filler. It is dense with URIs and repeats the resource-equivalence point already present in the schema's parameter description, which is minor redundancy.

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?

Given a single enum-constrained parameter and an existing output schema, the description covers everything an agent needs: when to use it, when not to, the fallback rationale, and a map of which guide to read for which downstream task.

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% and the enum lists all six URIs, so baseline is already met. The description goes further by explaining what each guide contains (markdown syntax, colours/styles/layout, task placement and dates), which the bare enum values do not convey — though overview/canvas/collections/blocks are lumped together rather than individually characterised.

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 ('Fetch an xTiles guide/documentation document') plus the addressing scheme (`xtiles://guide/...` URI). It is unmistakably distinct from other get_* siblings, which retrieve project/content data rather than documentation.

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?

Explicitly states the selection condition — use this only when the client cannot read MCP resources directly — and gives concrete prerequisites: read `xtiles://guide/markdown/overview` (plus canvas/collections/blocks) before calling any `*_from_markdown` tool. It names the sibling family it supports, leaving nothing to inference.

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