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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and a closed-world hint, so the safety profile is covered. The description adds genuine context beyond that: the results are limited to the Istanbul districts BilYe actually price-compares, and the output changes shape depending on whether 'ilce' is supplied. It does not describe ordering or formatting of the returned list.

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 definition is essentially one sentence with three tight clauses: the default listing, the parameterized mode, and the use case. The dual-mode behavior is front-loaded and nothing is redundant. The semicolon-joined structure is dense but still readable.

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 a one-optional-parameter read tool with full annotation coverage and no output schema, the description tells the agent what comes back (districts or neighborhoods) and when to call it. It leaves minor gaps, such as handling of an unrecognized district name and result ordering, that may matter for error recovery.

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% and the single optional parameter already documents that supplying it lists that district's neighborhoods. The description restates the same fact rather than adding new meaning such as accepted name formats, case sensitivity, or behavior for an unsupported district. Baseline 3 is appropriate when the schema carries the semantics.

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 states a specific verb ('listeler') and resource ('İstanbul ilçeleri' / 'mahalleler'), and it spells out both operating modes: no argument returns the price-comparable districts, while an 'ilce' argument returns that district's neighborhoods. This separates it cleanly from the sibling 'konumdan_ilce', which starts from a known location.

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 description names the situation that selects this tool: telling a user whose location is unknown which districts are supported. That is a concrete when-to-use condition. It stops short of explicitly naming alternative tools or stating when not to call it, so it is clear but not fully routed.

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