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

Annotations already declare readOnlyHint=false and destructiveHint=false; the description adds genuine value by stating 'Never publishes' (draft-only side effect) and 'May fetch external image URLs during import or screenshot rendering' (network behavior), consistent with openWorldHint=true. It stops short of noting rate limits or non-idempotency consequences.

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 and front-loads the core use case, then packs workflow steps into short imperative fragments. Every clause carries information, though the telegraphic fragment style is slightly choppy rather than smoothly structured.

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 17-parameter tool with nested objects and an output schema, the description covers the key workflow, precedence, media binding, external-fetch behavior, and non-publishing guarantee. Return values are noted even though an output schema exists, making it nearly complete, with only edit-vs-create routing left implicit.

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 76%, which already documents most parameters including the richDocument override rule and media slot bindings. The description reiterates the media.src binding (mediaFile1..mediaFile6 or mediaFiles) and the override precedence, adding little beyond the schema, so the baseline of 3 is appropriate.

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 opening sentence gives a specific verb and resource ('creating a Telegram draft'), which is clear and actionable. It distinguishes itself from publishing siblings via 'Never publishes,' but does not explicitly separate itself from update_post_draft or attach_media_to_draft, so sibling differentiation is partial.

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?

Strong workflow routing: 'Read get_formatting_capabilities,' 'prefer finished richDocument,' and 'Inspect preview_post' tell the agent exactly what to do before and after. It also gives a precedence rule (richDocument overrides text/preset/template). It lacks an explicit when-not-to-use clause or a pointer to update_post_draft for edits.

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