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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is fully covered. The description adds value by disclosing the shape of each returned item (slug, name, page URL), which compensates for the absence of an output schema. It does not mention ordering, total count, or whether the list is static/cacheable — gaps that keep this at a 3 rather than higher.

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 sentence that front-loads the resource and then lists the returned fields and their downstream use. Every clause earns its place; nothing is redundant with the title alone.

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?

With no output schema, the description carries the burden of explaining return values, and it does so by naming the three fields an agent will receive. What is missing is minor: nothing about list size, ordering, or stability. For a zero-parameter read-only lookup tool this is close to complete.

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?

The tool takes zero parameters, so there is nothing to disambiguate; the baseline of 4 applies. The description correctly avoids inventing parameter guidance.

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 names the resource (направления/темы афиши) and, crucially, tells the agent what each entry contains: slug, название, and the direction page URL. It also connects the resource to the sibling tool by identifying the slug as the value for search_events.directions. It stops short of an explicit verb like 'returns the list of', but the intent is unambiguous.

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 phrase 'slug для search_events.directions' effectively states the primary use case: call this to obtain direction slugs before calling search_events with a directions filter. There is no explicit exclusion or alternative-tool comparison, but the sibling routing is clear enough for an agent to act on.

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