twitter_user_login

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

Beyond annotations (readOnlyHint=false, destructiveHint=false), the description discloses that it stores a session server-side and does not return cookies, warns against logging credentials, and lists typical failure states (bad_credentials, two_factor_required, etc.). This is valuable transparency beyond what annotations provide.

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 a single dense yet compact paragraph that efficiently packs key info: purpose, dependencies, return format, typical failures, and security advice. It is front-loaded with the core purpose and doesn't include filler. Slightly dense but concise overall.

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 the tool's complexity (5 parameters, no output schema), the description fully covers the needed context: what it does, what it doesn't return, typical error codes with suggestions, and critical security warnings. It leaves no major gaps for an agent to misuse the tool.

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?

With 100% schema description coverage, the schema already documents each parameter. The description adds context: totp_secret is only required if 2FA, proxy_url is recommended to be a residential proxy (X treats datacenter logins as automated), user_agent should match the account's typical environment. These additional notes enhance parameter understanding beyond the schema.

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 uses a specific verb 'Log in' and targets the resource 'X' (account). It clearly states the purpose: authenticate and store the session for subsequent authenticated reads/writes. It distinguishes from siblings (e.g., twitter_account_me) by being the login action and explicitly not returning session cookies.

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?

It provides clear context for when to use: to authenticate before other account-scoped tools. It gives typical failure codes and how to resolve them. It doesn't explicitly mention when not to use or alternatives, but given the sibling set, there is no obvious alternative. Thus it lacks explicit exclusions but still useful.

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