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

Beyond the readOnlyHint annotation, the description discloses behavioral details that materially affect how the agent should act: it returns skillUrl links, requires the agent to fetch and follow a SKILL.md, and instructs fetching a personal skill-bundle via a specific endpoint after browser authorization. It also surfaces the retry-on-401-style behavior around AGENTPAY_API_KEY and sessionId.

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 long but each sentence carries operational weight: triggers, return handling, auth flow, and prohibitions. It is front-loaded with the core function in the first sentence. A few directives overlap thematically ('Never ask the owner to edit connector settings' vs 'Never ask owner to open Authorization settings'), which slightly reduces conciseness.

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 there is no output schema, the description reasonably explains what is returned (skillUrl links) and what to do next, including fetching the public SKILL.md and the personal skill-bundle. It also covers auth recovery and important never-do's. It doesn't specify the exact response shape or failure/empty cases, but for an agent invoking this tool the critical path is well covered.

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 already 100%, and both params are documented in the schema. The description adds value by explaining when sessionId should be passed in an auth-challenged context ('If AGENTPAY_API_KEY required and you already have sessionId from this chat: pass sessionId and retry') and implicitly links platform to the listed skills (Cursor/Claude/ChatGPT). This exceeds the baseline but doesn't deeply explain platform-specific behavior.

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 first sentence is specific and actionable: 'Fetch AgentPay skills index (skills.json) and install hints for Cursor, Claude Code, ChatGPT.' It names the exact resource, verb, and target platforms, clearly distinguishing this from siblings like get_faq or get_recovery_guide. The rest of the description reinforces the purpose with concrete triggers.

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 gives explicit when-to-use conditions: 'Call at session start when the user shops in Russia, after verify_connection, or when they ask «как подключить skill»...' It also provides clear negative guidance, including 'Never begin_agent_link again' and 'Never web-search,' which helps an agent avoid incorrect alternative tools or actions.

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