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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety behavior is covered. The description adds only that results are paginated, a point the cursor parameter schema already makes, and says nothing about rate limits or result shape.

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 with the scope filter front-loaded and zero filler. Every word contributes to identifying the tool.

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?

Six parameters, none required, no output schema, and a fully annotated, fully described schema mean the structured fields carry most of the burden. The description adequately conveys the media-only scope and pagination, though a note on default format or truncation behavior would round it out.

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 description coverage is 100%, so all six parameters (count, cursor, format, userId, username, max_chars) are fully documented in the schema. The description adds no parameter-level detail beyond what the schema supplies, so the baseline 3 applies.

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 ('Get a user's tweets') plus a narrowing filter ('that contain photos or videos'), which clearly separates it from the sibling get_user_tweets. It stops short of naming the alternative tools, so it is clear for the purpose but not sibling-routing.

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?

The media-only filter implies when this tool is appropriate versus get_user_tweets, but there is no explicit when-to-use, when-not-to-use, or named alternative. Usage must be inferred from the single filter phrase.

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