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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=true, openWorldHint=true) by disclosing patch semantics ('Only the fields you pass change'), a genuinely destructive sub-behavior ('the object you pass replaces the old links'), and an immutability constraint ('kind ... cannot be changed'). The ownership requirement also clarifies the auth boundary.

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 dense paragraph, front-loaded with the action and field list, then constraints, then the sibling escape hatch. Every clause carries information; nothing is restated from the name or 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 an 11-parameter mutation tool with a nested object and no output schema, it covers scope, ownership, patch/replace behavior, immutability, and the routing alternative. It stops short of describing any return value or error behavior, which is a minor gap given no output schema exists.

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 earns above that by adding the replace-not-merge semantics of the nested links object, which the schema does not state. The kind immutability note duplicates the schema's own text, so it adds no extra value.

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 (change) and resource (listing details of an app you own), then enumerates exactly which fields are in scope: title, tagline, description_md, category, tags, made_with, live_url, links. It also distinguishes itself from publish_app and implicitly from the HTML-editing sibling, so an agent can route without opening any schema.

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 precondition ('an app you own') and an explicit alternative with its trigger: 'To change the files, call publish_app with the slug.' It does not address update_app_html, a close sibling that also mutates an app, nor state any when-not-to-use beyond the file case.

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