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

Annotations already mark readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=true. The description complements these by explicitly stating 'Read-only' and describing the error behavior (unknown tagId returns error) and optional fields. No contradiction with annotations.

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?

The description is dense but every sentence adds value: purpose, examples, parameter details, error handling, and authentication. Front-loaded with the main action and concise enough to parse quickly.

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 no output schema, the description covers the return fields (id, name, description, coin_counter, ico_counter, optional coins/ICOs). It also discusses error handling and authentication. A minor gap: no mention of pagination or structure for the nested coins/ICOs lists, but that may be acceptable for a single-tag lookup.

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 low (33%) but the description adds meaning: tagId is a tag id from getTags (e.g., 'defi'), additionalFields is a comma-separated list of 'coins' and 'icos'. This explains the purpose and allowed values beyond the bare schema. The rationale parameter is described in the schema so the description does not need to repeat it.

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?

The description clearly states the tool fetches details for a single tag by ID, listing fields like id, name, description, coin_counter, ico_counter, and optional nested coins/ICOs. It provides specific example queries ('what coins are in the defi tag') and distinguishes from sibling getTags by saying 'To list every tag or find a tagId first use getTags.'

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 when to use: for queries about coins/ICOs in a tag. Includes step-by-step guidance: first use getTags to get tagId. Mentions error handling for unknown tagId and that no API key is required. This helps the agent decide when to invoke this tool versus alternatives.

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